Jason Segel and Michelle Williams have been spotted looking cosy at the premiere of his new movie The Five-Year Engagement.

The new couple did not hold back in showing their affection for one another at the event held at the Tribeca Film Festival, according to People magazine.

He was seen giving Michelle, 31, a kiss on the cheek as she left after the movie finished. She also kissed his cheek, said something in his ear and rubbed his back, before taking off. Jason stayed in the New York's Ziegfeld Theater to talk to friends and fans.

Jason was spotted holding Michelle's hand at the after-party in the Museum of Modern Art, and at one point pulled her behind a curtain.

Jason is the co-writer and star of the film about an engaged couple who keep putting off their wedding.

He earlier addressed his own plans for tying the knot in future.

"My plan is to get her to marry me as quickly as possible before she finds out who I really am," he said. "I'll do it romantic, but I'll do it like over a three-day weekend. We'll meet on Friday, have our first date on Saturday, engaged on Sunday and married on Monday."

Jason admits he is ready for a serious relationship. He is also willing to compromise saying he would "absolutely" relocate for a partner.

"I hit my thirties and enough became enough," he joked, not talking about Michelle specifically. "I'm ready to enter phase three. I put the puppets into a closet. I'm getting nice furniture."

However, he believes relationships take time to develop. He thinks couples should think carefully before they make a big commitment.

"A lot of people say 'I do' to a moment, but they don't realise they're saying 'I do' to a lifetime," he said.