Mary-Kate Olsen Gets Protective of New Beau

In romance news, don't mistake Mary-Kate Olsen for a pushover just because she's an anorexic, scary-looking, alien-like stick-figure.

The itty-bitty former Full House star maintained what is being called a "tight grip" on her rocker-looking "date" while making the scene at NYC hotspot Bungalow 8 with sister Ashley on Thursday night, the New York Post.

It seems Mary-Kate, who was reportedly seen getting up close and personal with Killers drummer Ronnie Vannucci a few days back, had good reason to be clingy. Trouble began brewing when Keith Richards' daughter, Alexandra, turned up and began eyeing MK's companion.

"[Mary-Kate] got into a huge fight with Alexandra and totally told her off," claims a witness, adding that the teeny teen twin "started full-on making out in territorial, 'this is my man' style."

Olsen has admitted she was crushed when Stavros Niarchos dumped her for Paris Hilton, and apparently doesn't want to get burned again.

Wow, Stavros Niarchos sure gets around... with the nastiest chicks on Earth.