Amanda Abbington has confirmed she is returning to Sherlock.

The actress told Vulture she would definitely be reprising the role of Mary – the wife of Dr John Watson, played by her real-life partner Martin Freeman – although she teased that she didn’t know what the future held for the couple.

“I am coming back, but I don’t know in what capacity,” she said.

“We don’t know storylines yet. Well, we do know some things, but aren’t allowed to say. What we do know is amazing.”

When the third series of the BBC show ended, Watson had forgiven his pregnant wife for lying about her past.

Asked if the couple would be good parents, Amanda said: “On the one hand, they’d probably be reckless because they’re both quite psychopathic. But I think an assassin and an army doctor who loves trouble, I mean, that kid has got nothing to worry about. Screwed up mentally, of course, but if there’s any bullying on the playground, we’re covered.”

Amanda also revealed how she was cast in Sherlock, which was created by Steven Moffat and Mark Gatiss, joking that it was ‘slight nepotism’.

The actress – who has also worked with Martin on productions such as The Debt, The Robinsons and The Good Night – explained: “I was sitting around the kitchen table at Mark Gatiss’s house one day, and he and Steven asked if I’d like to play her. I was honoured, I really was.

“Slight nepotism, but I’ve been working for so many years now that I think that’s fine. You can have a bit of nepotism now and again. And it’s such a joy working with him, Martin. He does every take differently, so you can really play.”