Ancelotti told French TV programme beIN Sport: "It's true that he's 37 but he's still a player.
"I remember a certain player who won the Champions League at 39 and his name is [Paolo] Maldini.
"He's 37 but still has the motivation and the physical condition . . . Beckham's not had many injuries in his career. He's one of the most serious and professional players I've ever known."