Boxer Chuck Wepner inspired Sylvester Stallone's Rocky films -- and the fact that he never got a cut of the billion-dollar franchise inspired him to sue.

Both events inspired The Real Rocky, the entertaining ESPN documentary that gives the colorful Wepner the chance to finally get his due.

The specific event that led to Stallone's Oscar-winning Rocky movie was Wepner's 1975 fight against Muhammad Ali. A 40-to-1 underdog, Wepner had put together an uneven record.

But his late-career surge convinced promoter Don King to give him a shot at heavyweight champion George Foreman. When Ali knocked out Foreman to take the title in the famous Rumble in the Jungle bout, a Wepner-Ali fight was scheduled for 1975.

Wepner, of course, did not emerge as the new heavyweight champ. But he did become one of only four fighters to knock Ali down, and when then-Hollywood wannabe Stallone saw the match, Rocky was born.

The Real Rocky -- Wepner was also nicknamed The Bayonne Bleeder by a sportswriter who witnessed him in a particularly gory battle -- went on to wrestle against Andre the Giant and a bear. All the while, he was promised a part in one of Stallone's movies. When it hadn't happened by 2003, he sued Stallone. The two settled for an undisclosed amount.

Wepner is about to get the big screen treatment again, this time in the upcoming biopic The Bleeder, starring Liev Schreiber.

The Real Rocky premieres tonight at 8/7c p.m. on ESPN.