Chris Pratt and Anna Faris have announced their separation after eight years of marriage.

The Guardians of the Galaxy actor, who shares four-year-old son Jack with Anna, took to his Facebook page to share the sad news in an official statement.

"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," it read.

"We still have love for each other, will always cherish our time together and continue to have the deepest respect for one another."

Chris and Anna's signatures concluded the statement, while Anna shared almost an exact copy on her Twitter page. However, Anna's version was missing the final phrase "and continue to have the deepest respect for one another."

The news has come as a shock to the majority of fans, considering Chris and Anna frequently gushed about their love for one another in interviews.

Anna, who was previously married to Ben Indra from 2004 to 2008, told the Huffington Post last year that Chris had changed her view on marriage.

"He is sexy, but more importantly he's a great person," she explained. "When I was falling in love with him, I loved how kind he was to people. I loved how smart he is, but he's not pretentious at all. He doesn't wear that as a badge - he kind of lets people slowly discover it.

"He's humble, and he's a great leader, and he's an incredible father and a great husband. And I feel like, after years of dating people that weren't the best for me, I found somebody who's love I could really accept."

Anna and Chris first started dating in 2007 after meeting on the set of their film Take Me Home Tonight, and the actor popped the question in November, 2008.

The stars tied the knot in an intimate ceremony in Bali, Indonesia on 9 July, 2009.