Becks works on his pecs � half-naked, on a piano � for a good cause!

David Beckham has done it on top of a piano in his underpants. Director Guy Ritchie has done it with his daughter on his back and Sons Of Anarchy actor Charlie Hunnam did it to rap music.

The three British celebs have all taken footage of themselves doing 22 press-ups over 22 days.

…