It’s not really the behaviour you’d expect of two grown men – especially not posh floppy haired actor Hugh Grant and PR ‘guru’ Matthew Freud.

But – during a £300,000 birthday bash for socialite Heather Kerzner – the pair engaged in the most un-usual punch-up!

Grant, 49, seemingly got into a row with Freud, 46, during the swanky rah rah dinner at crapola socialites hangout’ Annabel’s.

It’s claimed Grant used the c-word when he spotted Freud at the dinner – which prompted the PR to launch into his own attack on the actor – but not verbally – instead he chose a chocolate cake.

Minutes later the actor was smeared with a slab of chocolate down his trademark pristine white shirt - watched by ex-girlfriend Liz Hurley and billionaire Sir Philip Green.

It’s reported Grant then launched himself at Freud with an impressive right hook to the face and the two men grappled around like public school boys on a rugby pitch -before Freud left the party.

An onlooker and guest at the party said: “There’s no love lost between those two, but Hugh started it by being so ungracious.”

Freud said yesterday: “I saw a lot of white shirt and before I could stop myself it was all brown. I’m a pacifist, I only throw cakes. Grant’s a scrapper. There were no heroes.”

Annabel’s gave Grant a fresh shirt before he left the venue, after apologising to Heather – wife of hotel and casino mogul Sol Kerzner – for the the fracas.