On the heels of a report that Kristen Stewart briefly rekindled her romance with married filmmaker Rupert Sanders earlier this year, her ex, Robert Pattinson displayed heavy PDA with a new mystery brunette.

Pattinson was seen publicly holding hands with an unidentified brunette at a birthday party for Shoshana Bush in Los Angeles over the weekend, according to an eyewitness. Bush's event was held at film and television producer Allen Loeb's Los Angeles home. Loeb has worked on several films including Wall Street: Money Never Sleeps and Rock of Ages.

The eyewitness shared the details of the Pattinson sighting with a woman who is presumed to be his first real girlfriend since he split from Stewart in May.

"Rob and the brunette turned up around midnight. They were cute together," an onlooker told RadarOnline.

The source shared in detail the new couple's very public display of affection at the swanky event.

"At one point, he was talking to someone and she wandered over and grabbed his hand and pulled him to over to near the pool," said the onlooker. "Their hands were all over each other!"

The source said the mystery woman seems to be a good fit for the British heart-throb.

"She's really sweet and girl next door vibe. Rob is actually really nice and humble," the source shared. "They're a perfect match!"

The insider mentioned two other celebrities who also attended the lavish 25th birthday party-- Revenge star Christa B. Allen and The Hunger Games star Leven Ramblin.

Pattinson reportedly told Le Figaro  in a previous interview that he would love to like to have a French girlfriend. There is no word, however, if his new beau has a French accent.

Stewart was  romantically linked last month to her Camp X-Ray co-star Lane Garrison.

Garrison reportedly moved into the actress' Los Feliz home she once shared with Pattinson after they bonded during filming for their upcoming movie. Stewart plays a U. S. soldier stationed at Guantanamo Bay and Garrison plays a superior officer who forces himself on her.

"Kristen was enjoying Lane's company and he was spending a lot of time with her at her home," a source told Yahoo! Omg in a report published on Aug, 22. "He doesn't live in LA so he moved out of his hotel when they became close and moved into the guest wing of her house in Los Feliz."

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