Writing on Pratt’s official Facebook page, the couple said they “tried hard for a long time”.
“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 couple said they still have love for each other, will cherish their time together, and will continue to have the deepest respect for each other.
A big Mother's Day kiss and hug across the pond to my darling wife @annafaris and our sweet boy. I miss you both so much. I love you. Due to forced perspective in this picture Jack looks much bigger than Anna. How beautiful are they!? And the azaleas too! Richmond Park in full bloom. #happymothersdayAdvertisement
Fans were quick to comment and show their support to the couple.
"So sorry to hear this but glad that little Jack has two parents strong enough to understand the importance of putting his happiness and well being first," one person wrote.
"I know it's ridiculous to care about a relationship involving two people you've never met. I know it's crazy how much society today value celebrities and their lives. But I honestly am saddened to hear this just because they seemed so perfect for each other," added another.
Pratt and Faris, both 40, met in 2007 while they were filming Take Me Home Tonight. The couple married in 2009 and in 2012 they welcomed their son, Jack, into the world.