Here's one way to confirm a rumored new romance: Make your debut with a PDA display at a bash filled with the likes of Reese Witherspoon, Robert Pattinson, Kristen Stewart and Cameron Diaz.
The pair, who met last year on the set of "Wanderlust," reportedly stayed thisclose as they chatted with everyone from Pattinson to Jen's sometime co-star (and the ceremony's host), Jason Sudeikis, whom she was briefly linked to this time last year.
Among Jen and Justin's observed "unabashed" lovey-dovey behavior: He caressed her cheek, rubbed her neck and kissed her, while she "smiled ear to ear" as she adjusted his tie and leaned into him.
As Aniston played social butterfly and flitted around the A-list crowd, "Theroux looked on adoringly, and they exchanged kisses throughout the night."
Echoes a source to JustJared, "They looked very comfortable with each other. He had his arm around her for a good part of the night, and they even left the party holding hands."
But they apparently let go of each other's digits long enough for Justin to grope Jen's yoga-toned, could-bounce-a-penny-off-it butt before leaning in for another lip-lock, according to Us.
"Lots of sexual tension," opines a spy. "She [has] never seemed happier."
Aniston appeared to be in the same free-spirited mood on Thursday night, when she stepped out with Theroux at one of her favorite Los Angeles haunts, the Sunset Tower Hotel.
"They weren't even hiding anymore," relays a paparazzo (via X17). "She knew we'd spot her together with Justin, but she still left with him in the same car. Coming from her, that's as good as a press release announcing she has a new boyfriend!"
Jen has reportedly gotten the seal of approval from BFFs Courteney Cox and Chelsea Handler after recently hosting a small get-to-know-my-new-guy shindig.
"They all had a great time and enjoyed Justin's company," a spy told People. "He's edgier than the guys Jen usually dates. She really likes him!"
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