United Kingdom, Aug. 29 -- Benedict Cumberbatch believes a successful marriage requires constant work.

The 49-year-old actor stars alongside Olivia Colman in The Roses, a new comedy movie about a married couple experiencing relationship struggles, and Benedict has shared what he believes to be the key to a happy marriage.

The actor - who has been married to Sophie Hunter since 2015 - told the BBC: "Don't be complacent and keep the conversation between you going rather than thinking one of you is always right.

"It's also important to be tolerant, understanding and never stop working at it."

Benedict also revealed that he relished the experience of working with Olivia on the movie, observing that they have complementary acting styles. ...