Sherlock star Amanda Abbington has opened up about her "sad" split from partner Martin Freeman, saying that long periods spent apart were partly responsible for the relationship ending.
The 42-year-old actress said the Sherlock co-stars - who play married couple John and Mary Watson in the BBC1 detective series - "couldn't live together any more".
Abbington told the Daily Telegraph's Stella magazine: "It's all totally fine. Martin and I remain best friends and love each other, and it was entirely amicable, but we realised we'd come to the end of our time together.
"There was no hostility, really. We just said that we couldn't live together any more."
She said the separation - with Freeman, 45, now living in a flat in north London - was the start of "a new chapter".
"It is sad and it is upsetting because you think you're going to be with someone forever, but you either do that or you break up. And we both came to the decision that splitting was best for us. We've been really lucky to make it such a clean break, especially for the kids."
Abbington said the lack of time spent together - with Freeman filming The Hobbit franchise and US TV series Fargo abroad - was partly responsible for the end of the 16-year relationship.
"We've been apart a lot, and I think that's one of the reasons it happened," she told the magazine.
"You can't be away from people for too long, because you start to function on your own, you get used to being separate. You lose the connection and lose sight of it, in the end."
The stars, who have two children aged eight and 10, began filming the new series of Sherlock - in which their characters are first-time parents while their marriage also comes under strain - two weeks after they split.
The new series returns to TV screens on Sunday night.
Abbington admitted it was "so weird" filming the scenes, and added: "Especially playing new parents again... because we were effectively revisiting how it was when we first got together."
She said the pair occasionally questioned whether they were doing the right thing working together but that the answer was always "yes".
The actress, who is appearing on stage in a production of Abigail's Party, joked that she was "officially on the market" but added: "I haven't dated for 16 years, so I don't have a clue what to do. I certainly don't know what Tinder is."