Doctor Who star David Tennant is set to get reacquainted with alien lifeforms once again - but this time in an animated adventure as he voices a UFO-hunting character in a big-screen version of Fireman Sam.

The well-loved children's programme about the fire service in the fictional Welsh village of Pontypandy is getting a film spin-off, Fireman Sam: Alien Alert, due in cinemas in January 2017 and will feature Tennant, 45, as one of the lead characters.

He will voice Buck Douglas, the presenter of TV show Alien Quest, who is described as a humorous villain desperate to be a celebrity.

The film, which will mark Fireman Sam's 30th anniversary year, sees Buck and his TV show arrive in Pontypandy where UFO sightings are on the increase, but when a big stunt by Buck causes a forest fire, Sam has to fight to get the blaze under control and uncover what is behind the spate of alien incidents, as well as what the TV presenter is up to.

Tennant, who previously played Doctor Who in the BBC sci-fi series, said: "Fireman Sam is a true institution of children's television, so naturally it was a joy to be asked to guest-voice the character of Buck Douglas in the new special, Fireman Sam: Alien Alert.

"I had a lot of fun in the studio bringing Buck's character to life and I'm certain he'll be a big hit with audiences when he appears on screens throughout the world in the movie.

"He's slick and smug, but his adventurous and gregarious persona, as well as his UFO investigative adventures, makes the kids - and quite a few of the grown-ups - want to be just like him."

Senior vice president of global content and executive producer at Mattel Creations Christopher Keenan said: "It has been an absolute pleasure to have David Tennant on board as our guest-voice for Buck Douglas in the forthcoming Fireman Sam: Alien Alert."

He added: "He's worked on animation before so understood straight away what was needed from a technical point of view, and I guess his experience in the sci-fi genre might have helped him understand where his character was coming from."