03/28/2012 11:25 am ET Updated Mar 28, 2012

Michelle Williams, Jason Segel Dating; Couple Photographed Out And About

Michelle Williams is reportedly dating longtime friend Jason Segel, reports Us Weekly.

A source close to the couple confirmed to the magazine that the two are dating and added, "They are smitten and very serious."

Williams, 31, and Segel, 32, have been spotted together since late February in very "see and be seen" hot spots, which makes it seem as if they are ready to take the relationship public. They were spotted enjoying a meal at LA's Chateau Marmont on Feb. 27, and were again spotted dining at Comme Ca on March 16.

Just recently the new couple were spotted by photographers while taking a walk together after eating dinner at Frankie's Spuntino in Brooklyn on March 24. According to a witness the two got cozy and didn't seem to care who saw them together. "He put his arm around her and made her laugh as they walked. [They] seemed very relaxed," explained the witness.

Their unexpected coupling is not as unlikely as one might think. According to Us Weekly, the two have been friends for years and were introduced by Williams' good friend, former "Dawson's Creek" co-star and frequent award show date Busy Philipps, who worked with Segel on the short-lived show "Freaks and Geeks."

Williams and her 6-year-old daughter, Matilda, live in Brooklyn, while the "How I Met Your Mother" star is based in LA, but they are trying to make it work according to a source, who added, "She hasn't been this happy in a long time."

Williams dated actor Heath Ledger for three years, and had Matilda in 2005. The couple split up in 2007 and several months after his death in 2008 she began dating director Spike Jonze. Her relationship with Jonze lasted only a year and most recently the actress had been linked to director Cary Fukunaga, whom she was spotted cozying up to this past summer.

Segel had a six-year relationship with "Freaks and Geeks" co-star Linda Cardellini and their 2007 breakup was the inspiration for his hit movie "Forgetting Sarah Marshall." In 2009, the actor was linked to Chloe Sevigny and Michelle Trachtenberg.

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