The players have issued a statement appealing for Holly Wells and Jessica Chapman, who vanished from their homes in Soham, Cambridgeshire late on Sunday to go home.
The girls were wearing United shirts with DB's name and number on the back when they were last seen.
The statement said: "Please go home. You are not in any kind of trouble. Your parents love you deeply and want you back."
Detective Superintendent David Hankins: “We appreciate him (Becks) giving his time greatly - as do the parents of Holly and Jessica, I have no doubt.
"David Beckham and Manchester United have a tremendously high profile and an appeal from them may well have more impact with Jessica and Holly or with any of their friends."
Jessica's parents, Sharon and Leslie Chapman, later joined Holly's parents in issuing a joint statement thanking Beckham for his support.
The two families said: "It's tremendous, fantastic. To think someone like David Beckham would offer us his support is superb, coming on top of the local and national support we have already received. It makes our life that much easier at a very difficult time."