Brett Favre, Tim McGraw, Garth Brooks, Ashton Kutcher #Flex4Forces

Sun's out guns out!

The rich and the famous are showing off their biceps in the "Flex4Forces" digital campaign started by the USO.

The campaign has people show off their guns on social media and challenge friends and family to do the same in a show of support for the American military.

So far, we've seen the ripped arms of Tim McGraw, Brett Favre, Deanna Favre and Dak Prescott, the not so bad 55-year-old arms of Garth Brooks and the "do you even lift, bro" arms of Ashton Kutcher.

McGraw has a little gym freak to him. He's so ripped that he wore the tightest shirt ever made during his 2012 concert at Target Field.

We're waiting on Serena Williams to keep the movement going.

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