Little Mix have revealed that Mel C's appearance in their latest music video came as a complete surprise.

The quartet recorded a cover of Cameo's 80s classic 'Word Up' as this year's official Sport Relief charity single.

Its video sees the former X Factor winners strut their stuff in a gym and some famous faces make an appearance, such as Spice Girl Mel C.

However, Jade Thirlwall told the Daily Star that seeing one of their heroes on set came as a surprise.

She said: "Mel C is lovely. We didn’t even know she was going to be there and it was a total surprise. We was just dancing around in the video and then she came in, did her kick and left. I was like: ‘Oh my God, that’s Mel C, pretend to act normal girls’. She said: ‘Whenever you’re free you need to come to my house for lunch'."

Thirlwall added: "She brought her daughter so she could get a picture with us because she’s a big fan. I know how she felt. When I was little I was obsessed – I had Spice Girls wallpaper, the dolls, everything...”

Watch the 'Word Up' video below: