Kelsey Grammer has paid tribute to Frasier co-star John Mahoney following his death at the age of 77.

The actor posted a photo of him and his on-screen father on Twitter on Wednesday, writing: He was my father. I loved him.

Mahoney was one of the show’s most beloved characters, playing Frasier and Nile Crane’s cranky father Martin for 11 years.

The role earned him legions of fans and a Screen Actors Guild award, as well as two Emmy nominations and two Golden Globe nominations.

He died in Chicago on Sunday, but the cause of his death has not yet been announced.

Mahoney and Grammer appeared throughout the sitcom’s run, which spanned 263 episodes from 1993 to 2004.

The show’s casting director, Jeff Greenberg, has also paid tribute to Mahoney on Twitter.

He said: I’ve not known a kinder man nor more brilliant actor. We were all blessed to have spent 11 glorious years together.

Actress Peri Gilpin, who played Roz Doyle in the long-running series, tweeted a picture of Mahoney singing at her wedding.

She added: Watch Moonstruck, Say Anything and/or Frasier or anything you can with him in it and raise a glass to John. Remember him well.

After Frasier, Mahoney worked on Broadway and appeared as an elderly drag queen in an ER episode, with his last foray as an actor coming in 2015 in an episode of Foyle’s War.

The Blackpool-born star had been a latecomer to the industry, having moved to the US as a young man to study in Illinois before joining the US army.

He later taught English at Western Illinois University and served as the editor of a medical journal, before he eventually decided to try acting classes and joined the Steppenwolf Theatre in 1977, which propelled him into film.

(c) Sky News 2018: Kelsey Grammer pays tribute to Frasier co-star John Mahoney