Brittny Gastineau ATTACKED -- Black Eye From Vicious Beating in Hotel

Brittny Gastineau was savagely attacked in a West Hollywood hotel room and cops are now involved ... sources familiar with the situation tell TMZ.

Our sources say ... Brittny was at the London Hotel with a male companion -- a man who himself has some fame. We're told Brittny claims the man beat her up badly in the room ... so badly she had to go to the hospital.

Doctors at the hospital felt there was a domestic violence situation and called the police. We're told the police then came to the hospital and interviewed Brittny.

The injuries had to be gruesome, because Brittny was out last night (see pic) -- the attack occurred more than a week ago, and this is what she still looks like.