Arsene Wenger has included 17-year-old Jeff Reine-Adelaide in Arsenal's Champions League squad after impressive pre-season performances.
The teenage midfielder joined the club from Lens in the summer and could make his European debut for the Gunners after making the squad list alongside the likes of Alexis Sanchez and summer signing Petr Cech.
Clubs could name a maximum of 25 players on their 'A' list, as Arsenal did, and they also named seven youngsters on their 'B' list.
According to the UEFA website: "A player may be registered on List B if he is born on or after 1 January 1994 and has been eligible to play for the club concerned for any uninterrupted period of two years since his 15th birthday by the time he is registered with UEFA."
As such, Reine-Adelaide was ineligible for the 'B' list as he has only recently moved to Arsenal while 20-year-old Hector Bellerin, who has become a regular starter at the Emirates, has been included on that list.
There is also a place in the squad for forward Joel Campbell who has been linked with a move away from the club in the past.
Arsene Wenger's side were drawn to face German champions Bayern Munich, Olympiacos and Dinamo Zagreb in Group F.
Full Arsenal Champions League squad:
Goalkeepers: Ospina, Cech, Macey.
Defenders: Debuchy, Gibbs, Mertesacker, Gabriel, Koscielny, Monreal, Chambers.
Midfielders: Rosicky, Arteta, Wilshere, Özil, Ramsey, Cazorla, Flamini, Coquelin, Reine-Adelaide.
Forwards: Giroud, Walcott, Oxlade-Chamberlain, Sanchez, Welbeck, Campbell.