WENN 1 / 19

The Tribeca Film Festival was overflowing with adorableness on Wednesday night, thanks to new couple Jason Segel and Michelle Williams, who were glued to each other at the premiere of the actor's new flick, "The Five-Year Engagement."

"Michelle didn't do the red carpet but wanted to be there for Jason's big night," a spy tattles to Us Weekly. "She snuck in to sit in the theater during the screening, then they all went over to the afterparty together, where they were hanging out with his co-star Emily Blunt and Robert De Niro."

During the post-premiere bash at the Museum of Modern Art, Segel held tight to Williams' hand and whispered in her ear as he introduced her around, reports People, which kvells that they "looked very new and very happy."

And very touchy-feely.

"Michelle was really sweet but her usual shy self in crowds ... Jason would put his arms around her waist and they gave each other a few sweet pecks," adds the Us eyewitness. "They definitely seemed to have a physical chemistry. Every actor in there was so enamored by the couple!"

The funnyman's innate goofiness probably helped. According to the New York Daily News, he leaned down (way down) to give his petite squeeze a kiss on the nose and later had her (and everyone else) busting up as he danced around to Journey's "Don't Stop Believin'."

The actress ducked out of the festivities early, perhaps to head home to 6-year-old daughter Matilda, but she left Segel with a kiss on his cheek, a whisper in his ear and a fleeting back rub.

Their low-key appearance follows Jason's first and apparently only statement on the budding romance ("I think we would just very much like to be happy," he told "Extra." "That's all I'm going to say about it.") and snaps of the schmoopy decoration on his iPhone cover, on which he's taped pics of Williams surrounded by the words "I love you."

(Go on and say it -- we know it's welling up like an eruption at Old Faithful: Awwwww.)

And though Williams lives in Brooklyn and Segel is based in Los Angeles, the long-distance issue may not be much of a problem.

When People asked the actor if he would ever take a cue from his "Five-Year Engagement" character and relocate for love, he responded, "I would, absolutely."

He also sounds a whole lot more man than Muppet these days: "I hit my 30s and enough became enough. I'm ready to enter Phase 3. I put the puppets into a closet. I'm getting nice furniture."


'Smitten and serious' Jason and Michelle take romantic stroll

Jason and Michelle's laughter-filled date night

Jason talks 'Five-Year Engagement'