Duncan was born an entertainer, starring in school productions and starting his professional career working at a Haven holiday camp, where he was to meet his soon-to-be bandmates Lee Ryan, Simon Webbe and Antony Costa. Blue, the pop group, was born in 2001.
They exploded onto the scene and amassed huge commercial success, but in 2005 they decided to take a break from the band to pursue other interests, and Duncan saw this as the perfect opportunity to broaden his experience within the entertainment industry.
He starred as Billy Flynn in the hit musical Chicago, and became a familiar face on television, working as a presenter on Soapstar Superstar, Capital FM's Party In The Park, City Hospital, T4, The Clothes Show and GMTV’s Entertainment Today. He made his television acting debut in Plus One for Channel 4, in which he played a tongue-in-cheeks of his Blue persona, with the series being acclaimed by both critics and the public. He went on to play the role of Ryan in the popular soap opera Hollyoaks.
He has appeared in pantomime including the title role in Jack and the Beanstalk, Prince Charming in Cinderella, and Aladdin in Aladdin. Recent musical theatre performances include Priscilla Queen of the Desert UK tour, reprising his role in West End's Chicago, and the UK and Ireland tour of The Rocky Horror Show.