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Entertainment Tonight.Matt Damon made a cameo appearance on Sunday's episode of "Entourage." He fought to encourage Vince, played by Adrian Grenier, to donate to donate to real-life charity ONEXONE.

In anticipation of Sunday's broadcast, Jeremy Piven tweeted, "End of season 6 tonight and it's our best, no doubt..."

In the episode, Damon tried to enlist the star power of Vince to travel on a mission to Ohio to help fight hunger amongst children. Work obligations prevented Vince from going on this trip, but Damon wouldn't let him get off that easy. Showing true dedication to the charitable cause, Damon asked Vince to donate money in a sequence of phone calls and conversations that escalate at times to quite a heated exchange of words.

Bono and LeBron James also appeared in the season finale of the hit HBO show to pressure Vince into contributing to this philanthropic effort.

ONEXONE raises money to improve the quality of life of children both domestically and abroad. To see videos from Damon's visit to the set of "Entourage," click here.