Kiefer Sutherland Head-Butts Fashion Designer

Celebrity fashion designer Jack McCollough was allegedly headbutted by actor Kiefer Sutherland at a party in lower Manhattan early Tuesday morning.

Denying he initiated any altercation, he's slamming reports that he provoked the 24 star, who said he only acted to protect actress Brooke Shields.

"Anyone who knows Jack McCollough knows that he would not hurt a fly," a rep for McCollough, of the New York fashion empire Proenza Schouler, said.

"All we can say at this point is that he was the victim of a vicious, violent, unprovoked assault and that the matter is in the hands of the authorities."

Jack McCollough's nose was broken in the incident.

One report claims that Jack McCollough bumped into fellow MET gala guest Shields, prompting Kiefer Sutherland to get physical with the designer.

But New York's Daily News says McCollough – a friend of Shields' – interrupted her and Sutherland while they were speaking outside the SoHo nightspot SubMercer, and Sutherland head-butted him after the two men exchanged words.

Another guest says Kiefer demanded Jack apologize to Brooke - for what, no one knows - and Jack allegedly pushed Kiefer, who headbutted Jack.

In any event, the altercation came as a surprise to bystanders:

"Jack walked into the party and tried to order a drink, and then the next thing he knew, he got headbutted for no identifiable reason." [McCollough] did nothing other than walk into a party. He did not bump into Brooke Shields. It's just puzzling.”

The NYPD said the incident remains under investigation.

For her part, Shields' rep said "nothing happened to her," adding "Jack did nothing inappropriate. It's not clear what caused Kiefer to do what he did."