Naomi Ackie had to wear a set of false teeth to play Whitney Houston in a new biopic.

The 30-year-old actress portrays the late superstar in new movie-musical 'I Wanna Dance With Somebody' - and Naomi spent weeks perfecting her American accent only for it all to go horribly wrong as soon as she put in her specially-made teeth.

During an appearance on 'The Graham Norton Show', she explained: "I had been working on the [American] accent for six months and thought I had it down, then suddenly putting in the fake teeth meant I had to learn it all over again."

However, she still managed to fool most of her castmates who "freaked out" when they realised she's British.

Naomi added: "People freaked out when they heard my British voice. On set I would be talking as Whitney and then afterwards I was like, ‘Bloody hell, that was a hard day innit!'"

The actress also explained that she totally immersed herself in the world of Whitney to play the tragic singer - who died aged 48 in 2012 - and she ended up having to stop listening to the star's music for a while.

She added: "I had to take a break because I really was immersed in her world. "

However, after some timed had passed Naomi felt able to revisit the superstar's hit. She went in: "Now I listen to her to remember some of the moments I had filming. It was such a formative time in my life and career that I look back on it fondly.”

'The Graham Norton Show' airs on BBC One on Friday December 16 at 10.40pm. It is also available on BBC iPlayer.