We know there's plenty of air-kissing and mutual adoration in luvvie land.

But Charlize Theron has taken all that schmoozy schmaltz to a higher level - by literally kissing the backside of a Hollywood heroine.

The Monster Oscar-winner felt the need to pucker up at the Premiere Woman In Hollywood Event while paying tribute to movie veteran Shirley MacLaine.

Words were not enough for the blonde A-lister, so she stepped down from the stage to plant one on Shirley's bum.

Theron, who received an award herself during the evening's entertainment, blamed her hi-jinks on painkillers she was taking for a neck injury, picked up filming sci-fi movie Aeon Flux.

"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 gushed to the press.

"She loved it," Charlize added. "She said it was the best she's had all year."

And it appears Shirley really was grateful for the backside-based compliment.

"I've gotta get to know her," MacLaine told IMDB.com. "I should get drunk with her,"

Now that's a night out we'd all like to witness.

Source: Press Release