Sylvester Stallone did indeed get his first movie acting role in a porn movie, called Party at Kitty and Stud's. This movie came out in 1970, when Sly was but
Stallone made the most of his break, quickly entering mainstream movies with a role in Woody Allen's Bananas the next year. He appeared in six more films before 1976's Rocky, the role that shot him right to the top. The canny Sicilian wrote the script for Rocky and sold it for a very low price, on the condition that he star in the movie and receive a share of the profits. Rocky went on to win three Oscars, including best picture. It made Stallone's movie career.
Whoever owned the rights to Party at Kitty and Stud's capitalized on Stallone's new-found fame by
Party at Kitty and Stud's/The Italian Stallion started life as a genuine pornographic
At one point Kitty confides to one of her friends that Stud is "so far out" and "animalistic." At another point Sly enjoins Kitty to "be careful! You bit me last time." Kitty replies, "I'll be velvet-mouthed on your shank of love!" before dissolving into an unscripted fit of giggles only partially concealed by burying her head on Stallone's shank of love. Stallone's best scenes are the ones where he is naked (which is nearly all of them). The highpoint of the film is probably Stallone's helping three women, one after the other, although all the overt details are edited out, leaving just the moaning and groaning.
Sly-connoisseurs will note that he has a four-inch scar on his left thigh under his butt. Far from being a stallion, Sly is actually a man of quite ordinary, even modest, endowment. His muscular frame, lacking its customary coat of oil, is unimpressive. Some people claim to see undertones of Rocky in Party at Kitty and Stud's, but I couldn't detect any myself, unless they mean the scene where Sly lightly beats Kitty
with his pants belt. Sly lacks his trademark sneer and talks normally in Party at Kitty and Stud's.
It is not unknown for a porn movie performer to cross over into mainstream cinema. Traci Lords renounced her porn film past and took minor roles on television, such as a dental assistant on the TV sitcom Married with Children.