HE'S KNOWN as one of Scotland's most distinguished actors, renowned for starring roles in Braveheart and Game of Thrones. Now, however, bookies are predicting that James Cosmo looks set to be the unlikely winner of Celebrity Big Brother.

The 69-year-old actor who is currently starring in Trainspotting 2 as the father of the loveable anti-hero Renton, played by Ewan McGregor, has had roles in some of the biggest hits in Scottish cinema. He played Angus MacLeod in Highlander, and Campbell, the father of Brendan Gleeson's character Hamish in Braveheart. He also starred in The Lion the Witch and the Wardrobe, Troy and Ben-Hur.

Eyebrows were raised when he took his place in the Big Brother house along with the likes of Geordie Shore reality star Chloe Ferry, TV presenter Kim Woodburn of How Clean is Your House, and model and reality TV regular Bianca Gascoigne, the stepdaughter of footballer Paul Gascoigne. Others in the long running celebrity show, now in its 19th season, include Loose Women star Coleen Nolan, Irish singing twins Jedward and Callum Best.

Yet the unlikely reality star is now odds-on favourite to win the final this Friday. Both Sky Bet and Paddy Power are placing him as joint favourite along with Jedward at 9/4. Coral are offering odds of 5/2 on his victory with BetVictor also offering 9/4.

Some popular cultural commentators have raised questions about why an actor of his standing is taking part in the first place. Celebrity gossip site Digital Spy noted: "We can only assume he's an absolutely massive Big Brother fan...he's way too good for that house".

The gravel-voiced Scot, originally from Clydebank, has won over his fellow housemates, who voted for him to be granted "eternal immunity" from the Celebrity Big Brother public vote, which means he assured a place in the final next Friday.

His appearance hasn't been without controversy - in one episode the actor admitted to having had a "violent past" telling housemate and American singer Stacy Francis: "For the majority of my life until I met my wife, I was not in a good place. I was not a good man. I've been violent in the past." All that changed, he claimed when he met his wife and had a son.

Meanwhile fans are hoping the bookies are right to put their faith in him as the winner. One commented on the Digital Spy forum: "I'd love him to win over all the try-hards in there. Doing nothing except being charming and a nice person is such a rarity on this show. So he's my choice of winner." While another, referencing his Trainspotting fame quipped: "Choose Life...Choose Cosmo".

It is now 20 years since the original Dutch show Big Brother, which takes its name from the character in George Orwell's 1949 novel Nineteen Eighty-Four, was created by producer John de Mol in 1997. It premiered in the UK in 2000 and heralded in a new age in ubiquitous reality television shows. A year later spin-off celebrity Big Brother was born and remains a popular culture phenomenon to be reckoned with. Series producers claimed viewing figures jumped from 1.3million to 2.3million last week after a series of violent verbal outbursts from 74-year-old Kim Woodburn.

Gladeana Mcmahon, one of the UK's leading psychological advisors for reality TV, agreed that Cosmo was unlikely to have taken part to raise his profile. "People take part for many reasons," she said. "For existing celebrities it is often just a job for which they get paid and get exposure from. However, for some it's about the experience as they are in the enviable position of being able to chose."

Mcmahon, who was the driving force behind the "Ethical Guidelines for Reality TV" produced by the British Association for Counselling and Psychotherapy, said it was important that individuals were "emotionally robust" but admitted: "Sometimes individuals do regret taking part. Even celebrities have had difficulties...Jade Goody, Fearn Britain and Vanessa Feltz to name but three. All came out to a hostile reaction."