Lily Allen picked one of her own impersonators to appear in her latest pop video.

The singer is heavily pregnant and was unable to attend the shooting of new track '5 O'Clock' - which features a sample of her song 'Who'd Have Known' - by T-Pain, so sent a body double instead.

T-Pain explained: "The girl was actually a Lily Allen impersonator to mouth her words for the track.

"The girl in the video looked like her, she picked the girl to mouth the song. She would've been in the video but she's all fat right now. And I didn't want her all preggers in the video."

T-Pain has long been a fan of the British singer but it wasn't until he heard the track as hold music that he heard the part he wanted to sample.

He added: "I'm a big fan of Lily Allen, I've seen all her videos, I like all her singles. She's doing pretty well and stuff and I thought, 'I gotta get myself onto that'.

"I first heard the song when I phoned the Apple store and they put me on hold, and it was playing. I had heard the song before, but never from the beginning, so that put a whole new life on the song for me, that was my favourite part, so why not sample it."

He also admitted Lily's distinctive voice played a part in his choice to sample the track. T-Pain also said he is planning to hang out with Lily - who married Sam Cooper earlier this year - when she has her baby.

'5 O'Clock' is released on December 4 and T-Pain's album, 'rEVOLVEr', is out on December 5.