The former 'EastEnders' actress and the 'Miranda' star announced the news in a statement on Thursday, just a year after they welcomed their second child.
"Tamzin Outhwaite and Tom Ellis are sad to confirm they have separated," it read.
"They continue to support each other as parents and will remain friends. They ask for sensitivity at this difficult time."
The couple met in 2005, and were married year later.
They have two daughters, one-year-old Marnie Mae and four-year-old Florence.
Tamzin has recently joined the cast of 'New Tricks' as DCI Sacha Millard, who will be replacing Amanda Redman's character.