Some of the game's finest fledgling players may have already earned their stars at club level, while others are hoping to put themselves on the map by sparkling at Euro 2024.
The 24-team talent pool is packed with teenage talents and those who have only recently celebrated their 21st birthday, some of whom we have cherry-picked as the breakout stars to watch at this summer's tournament.
Euro 2020 saw a new record set for the youngest player to appear at the championships - Kacper Kozlowski was just 17 years of age when he donned the Poland strip - but the now-20-year-old could be dethroned in Germany.
Here, Sports Mole selects the stars aged 21 and under to keep an eye out for at this year's European Championships.
Jude Bellingham - England
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No introduction is necessary for this one, and it is still so easy to overlook the fact that England and Real Madrid hotshot Jude Bellingham is still just 20 years old, although he will turn 21 on the weekend of the last 16.
Living up to the extremely high potential he displayed at Birmingham City and then Borussia Dortmund, Bellingham exceeded expectations and then some in a Real Madrid strip. Twenty-three goals, 13 assists, one Champions League and one La Liga, what more could Carlo Ancelotti ask?
Bellingham was not involved in either of England's warm-up friendlies as he earned a long-overdue rest, although the Three Lions' lacklustre attacking displays in both matches certainly highlighted just how crucial the 20-year-old will be if the Three Lions are to justify their favourites label.
Lamine Yamal - Spain
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Onto another La Liga phenom and the man who is destined to break the record for the youngest man to ever play a Euros match, Lamine Yamal of Barcelona has sent many a record tumbling during the first year of his club and national team career.
Already a mainstay of the Blaugrana XI at the tender age of just 16, Yamal directly contributed to 17 goals from 50 games last season and has provided four assists in his last two matches for Spain, whom he is also the youngest male appearance-maker and scorer for.
Of course, Yamal's unrelenting run of fixtures in 2023-24 has led to fears about potential burnout and long-term career impacts, especially with the Barcelona attacker also eligible to represent Spain at this year's Olympic Games.
Florian Wirtz - Germany
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While Bayer Leverkusen's astounding unbeaten streak in 2023-24 was a monumental team effort, embryonic playmaker Florian Wirtz is undoubtedly the jewel in Xabi Alonso's crown.
Picking up right where he left off after a crushing ACL injury, Wirtz was the scorer of 18 and assister of 20 goals for the Bundesliga champions last season, earning him a plethora of individual accolades, including the Bundesliga Young Player of the Year prize.
Thanks to Germany's status as hosts, Wirtz has not tested his international mettle in a competitive setting since before his ACL injury in 2022 and has made his case to be one of the first names on Julian Nagelsmann's team sheet, whether that be out wide or in his favoured number 10 role.
Jamal Musiala - Germany
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Wirtz is just one of two 21-year-old playmakers hoping to light up German stadiums across the land over the next few weeks, as Bayern Munich's Jamal Musiala has some domestic wrongs to right at Euro 2024.
Despite contributing 12 goals and eight assists in 35 games across the Bundesliga and Champions League, Musiala and Bayern suffered a rare trophyless campaign, and several clubs are supposedly trying to entice the ex-Chelsea man away from Bavaria.
Real Madrid, Manchester City and Liverpool have all been linked with a move for Musiala, who briefly donned the England colours at youth level before pledging allegiance to Germany, whose fans continue to be dazzled by his exhilarating dribbling ability.
Kobbie Mainoo - England
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The international status of Manchester United starlet Kobbie Mainoo was also up in the air for a short while, but as the 19-year-old started to excel in a Red Devils kit, the FA fast-tracked his rise up to senior level for England.
After his start to the 2023-24 campaign was hindered by an ankle problem, the 2005-born protege wowed Erik ten Hag with a spate of dynamic midfield displays as well as a couple of noteworthy goals, including a terrific solo winner versus Wolverhampton Wanderers and a well-taken finish in the FA Cup final.
Only one spot in the England engine room alongside Bellingham and Declan Rice is up for grabs, and while Mainoo - like almost all of his teammates - was not at his best in the recent friendly loss to Iceland, he made an extremely strong case for Euro 2024 starts throughout the domestic campaign.
Benjamin Sesko - Slovenia
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Set to be at the centre of one of the most intense transfer auctions in the summer window, 21-year-old RB Leipzig and Slovenia number nine Benjamin Sesko is being tipped to become the next star striker for either Arsenal, Chelsea or Man United.
Formerly of the famed Red Bull Salzburg academy, Sesko scored in all of his final seven Bundesliga appearances for Leipzig last term and also shone for Slovenia in Euro 2024 qualifying, registering five strikes and setting up two more.
Slovenia's pre-Euro 2024 form has been exceptional, and the towering 6ft 5in Sesko has played a crucial role in that, particularly impressing with his ruthlessness when chances present themselves to him.
Warren Zaire-Emery - France
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Kylian Mbappe may have finally cleared out his Paris Saint-Germain locker, but the Parc des Princes faithful have a new home-grown talent to sing the praises of in the shape of 18-year-old midfield starlet Warren Zaire-Emery.
The 2006-born lynchpin has already racked up 74 appearances for the Ligue 1 champions - starting 21 top-flight games last season - and he scored on his France debut in their 14-0 destruction of Gibraltar before his baptism was cruelly cut short by an ankle problem.
However, Zaire-Emery recovered quicker than expected and was a straightforward pick for Didier Deschamps, although Under-23s boss Thierry Henry saw his request to also select the teenager for the Olympic Games turned down.
Xavi Simons - Netherlands
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From a current PSG protege to one whom Les Parisiens initially let slip through the net, Xavi Simons failed to cut the mustard in the French capital but burst onto the scene in his native Netherlands with PSV Eindhoven, seeing the Ligue 1 champions trigger their cut-price buyback clause.
Rather than be re-integrated into the PSG ranks, though, the 21-year-old was again sent out on loan to RB Leipzig, where he scored 10 goals and set up 15 more, and he has quickly become one of the first names on Ronald Koeman's Dutch team sheet.
Whether Simons's future still lies in Paris remains to be seen, but standout performances at Euro 2024 could trigger an even more chaotic scramble for his services.
Rasmus Hojlund - Denmark
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It was perhaps unfair to expect Rasmus Hojlund to set the Premier League alight with Manchester United, who had previously done their utmost to win the race for Harry Kane before taking a punt on the 20-year-old kid from Denmark.
Now another year older and wiser, the striker can reflect positively on a 16-goal debut season at Old Trafford, striking 10 times in the top flight and on five occasions in the Champions League, while collecting an FA Cup winners' medal to boot.
Furthermore, no player in Denmark's Euro 2024 qualifying group scored more times than Hojlund's seven, and his physical presence should certainly cause some problems for a Harry Maguire-less England troupe.
Joao Neves - Portugal
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One teenage talent tipped to join the likes of Mainoo and Hojlund at Old Trafford next term is Benfica protege Joao Neves, part of the Portugal selection for this summer's tournament after filling the Enzo Fernandez-sized void expertly.
Neves was just 11 years old when he watched the Selecao conquer the continent in 2016, but he heads to Germany on the back of making 55 appearances for Benfica in the 2023-24 campaign, and six Portugal caps have already come his way.
The Selecao's 4-2 friendly success over Finland on June 4 saw the 2004-born youngster both make his first start and complete the full 90 minutes for the senior Portugal side, who have surely found a solution to their defensive midfield quandary for at least the next 15 years.
Georgiy Sudakov - Ukraine
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From a talented number six to an eye-catching number 10, Shakhtar Donetsk's Georgiy Sudakov has long been tipped to leave his homeland behind and earn his stars in Europe's big leagues, having already racked up over 100 matches for his current club.
The 2023-24 season saw the 21-year-old bag 10 goals and set up another six - including a strike against Barcelona in the Champions League - and he was named to Ukraine's Euro 2020 squad but failed to earn a single minute at the tournament.
Three years later, Sudakov set up both of Ukraine's goals in their playoff final triumph over Iceland, prior to which he also scored three times for the Under-21s during their run to the Euro 2023 semi-finals, offering further hope that he could shine in the blue and yellow again this summer.
> Click here to see our top senior players to watch at Euro 2024
