The TV star - who last week admitted she was looking for a new man following her separation from husband Alex Reid - was seen getting cosy with the light welterweight world champion at a star-studded bash at the lavish London Hotel in Sunset Boulevard, Hollywood.
According to fellow guests, at one point Katie, 32, and Amir, 24, started playing "sexual" games by seductively licking ice cream canapes with each other at their table.
An onlooker told Britain's The Sun newspaper: "There was No Doubt to anyone in the room there was something going on.
"First he had his arm around her and they were very touchy-feel. After a few minutes he touched her bum and she absolutely loved it.
"Then a waiter brought them some canapes and they turned it into something sexual. He was licking the ice cream seductively and they started giggling and hugging. They were all over each other."
But last night (27.02.11), Amir told his fans the fun ended there and insisted he went Home Alone from the bash.
He wrote on twitter: "If anything comes out about me and Katie Price being at an Oscars party and spending a night together, it's not true. I was in bed alone at my own place for 11pm and was up @ 8am to train. Just to make it clear. I didn't no she was gona be there. (sic)"
The pugilist also claims he wouldn't strike up a romance with mother-of-three Katie because he is friends with her estranged spouse Alex.
He said: "He's an MMA (mixed martial arts) fighter and we've talked about training together and we are friends so I would never do anything to mess with that. He'd kill me."