Rumours circulated of a romance after the pair, who have previously been spotted enjoying nights out together, were reported to have kissed at an LA party.
But the boxer told the Daily Mirror: “I don’t know why people are saying we’re together because it is absolute, total b*******.
“We’ve never been anything more than friends and we never will be – I am actually dead good mates with Alex.
“He’s an MMA fighter and we’ve talked about training together and we are mates so I would never do anything to mess with that. He’d kill me.”
Both he and Katie were in LA over the weekend to attend Elton John’s annual pre-Oscars dinner.
Amir continued: “I will catch up with Katie tonight for a drink and a laugh but nothing more than that – if anyone says we are more than mates that’s a load of crap. I am single and enjoying the single life.”
As to the kissing rumours, he insisted Katie had simply leaned in to talk over the loud music during a party at LA’s London hotel when onlookers mistook their conversation for something more.
The glamour girl, 32, is rumoured to have signed a deal with Paramount over the weekend for a biographical film of her life.
She tweeted a message to her fans saying: “On my way to sign a (sic) exciting deal woo.”
According to the Sunday Mirror, it will tell the story of how she went from topless model to head of a £40 million business empire.