Theron puckered up to pay homage to her heroine at the Premiere Icon party on Tuesday night and stepped down from the stage to plant her lips on MacLaine's posterior, reports the Internet Movie Database.

A red-faced Theron blamed her show-stopping tribute on the painkillers she was taking to combat an aching neck. She said: "It was a combination of my painkillers and the fact that everybody was paying tribute to this incredible woman, this incredible actress, so I had to go to the physical aspect of kissing her a**."

Theron, who was honored alongside MacLaine and Lindsay Lohan at the Hollywood bash, admits she was amused with her heroine's response: "She loved it. She said it was the best she's had all year."