'RHONY' Allies! New Housewife Tinsley Mortimer MOVES In With Sonja Morgan

Sonja Morgan not only has a new man, she has a new roommate.

The Real Housewives of New York star, 53, invited her longtime friend and new costar Tinsley Mortimer, 41, to move into her Upper East Side home, RadarOnline.com can confirm.

"Tinsley just relocated back to New York from Palm Beach, and is now staying with Sonja," says a source close to the Bravo stars.

With her teen daughter Quincy away at boarding school, Morgan's "loving the company," the insider adds. "Sonja thinks Tinsley is delightful!"

As RadarOnline.com previously reported, Mortimer joined RHONY this fall after she was arrested in April for trespassing at the Palm Beach home of an ex-boyfriend.

Looks like the newbie will be on Team Sonja in Morgan's epic feud with LuAnn de Lesseps, who married her former friend's ex-lover on New Year's Eve. (Meanwhile, Morgan is currently dating nightlife guru Rocco Ancarola.)

Only Dorinda Medley attended the Palm Beach ceremony, as Morgan vacationed in Thailand and de Lesseps public enemy #1 Bethenny Frankel hit the beach in Mexico with boyfriend Dennis Shields.