David Beckham may be retired from soccer but he still keeps in tip-top shape and proved it when he posted video of himself doing the 22 Million Pushups Challenge he accepted after Guy Ritchie called on him to get involved.

The viral campaign, which was brought about to bring awareness to the 22 U.S. veterans suffering from post traumatic stress disorder who commit suicide everyday, has brought out an array of different celebrities challenging one another to do push-ups for the cause.

The 41-year-old has vowed to do the challenge for 22 consecutive days and has shared videos daily via his Instagram account of him doing his part.

In our favorite one he upped the ante by doing the push-ups in his underwear, over a piano, 79 stories up and did we mention in his underwear?

Beckham went through his push ups with ease as the piano played.

The pianist on the keys is his best friend, sports agent and Liv Tyler's partner, David Gardner.

Becks has now nominated his son, Brooklyn Beckham and Jen Aniston's hubby, Justin Theroux, to take the challenge.

For more information about 22 Million Pushups visit 22kill.com.