Chris Pratt Was in 'Great Spirits' in Recent Weeks Before Revealing Split from Anna Faris

Just two weeks before publicly announcing his separation from wife Anna Faris, Chris Pratt seemed relaxed and happy at the premiere and after-party for his former Parks and Recreation co-star Aubrey Plaza‘s new movie, Ingrid Goes West.

A partygoer tells PEOPLE that Pratt “was friendly, outgoing and playful” at the after-party, adding, “I was surprised by how he looked to actually be having fun, and that he was there voluntarily.”

Another onlooker who attended the bash at Avenue L.A. adds that “Chris seemed different, like he was ‘free’ almost.”

“He said no to pictures though, which is weird because he always likes to take photos with fans,” the onlooker says. “But he was in great spirits and was mingling with everyone he knew, like Amy [Poehler], Aubrey [Plaza] and that whole crew. They were together the whole night.”

The party marked a Parks and Recreation reunion, with Pratt, Poehler and Plaza also hanging out with castmate Retta.

In their social media statement on Sunday night, Pratt, 38, and Faris, 40, said, “Anna and I are sad to announce we are legally separating. We tried hard for a long time, and we’re really disappointed.”

“Our son has two parents who love him very much and for his sake we want to keep this situation as private as possible moving forward,” the statement continued. “We still have love for each other, will always cherish our time together and continue to have the deepest respect for one another.”

The former couple was married for eight years, and share a son, Jack, who will turn 5 in August.

The pair had been plagued with rumors of tension over the past year, and Pratt was recently spotted without his wedding ring in public.

A source tells PEOPLE Faris sometimes seemed unhappy while Pratt was away filming and that the separation was often hard for her to bear.