Patrick Schwarzenegger swears he didn't betray girlfriend Miley Cyrus while partying in Cabo San Lucas, Mexico over the weekend.
Though new photos captured the 21-year-old model hugging and linking arms with a brunette sorority girl in a black bikini at Mango Deck Restaurant & Bar, he insists the woman was just a friend.
"Omg. It's one of my best friends' girlfriend," he tweeted this afternoon. "Would NEVER do anything against me GF…Girls Have guy friends and guys have friends that are girls…"
A partygoer named Isaac exclusively tells RadarOnline.com that the famous University of Southern California student was just having some innocent fun.
Schwarzenegger and a group of five friends were "having a time good, drinking shots and beers," Isaac tells Radar. "Patrick and the girl were jumping around and hugging each other, but there was nothing compromising going on."
As for the touchy-feely behavior, Isaac shrugs.
"It's spring break," he explains. "Everyone was drinking!"
Meanwhile, singer Cyrus, 22, seems to have stayed home in Los Angeles after her man took off for typical college festivities with his pals.
The couple started dating last fall.
Should Miley be mad at Patrick? Sound off in the comments.