Ayda Field and Robbie Williams. Picture: Bang Showbiz

Ayda Field claims she and Robbie Williams had sex backstage at 'The X Factor'.

The 'Strange Wilderness' star confessed she and the 'Angels' hitmaker - who were joined on the judging panel by Louis Tomlinson and show boss Simon Cowell - enjoyed a series of romps whilst they were waiting for the adverts to finish during filming the ITV talent show.

During tonight's festive episode of 'Celebrity Juice' on ITV2, she spills: "It's surprising how much f***ing you can do in the ad breaks."

The UK panel show's host Keith Lemon then pressed the actress for more details on the couple's sex life and she quipped about "faking orgasms", joking that "the only kind of orgasm I know how to have."

Ayda's sex confession comes after Robbie admitted he thinks his marriage improved when they started working on the show this year.

The 44-year-old pop star appears claimed that in spite of their on-screen rivalry, the pair have actually benefited from working together. 

He said: "We were a really tight unit anyway and when people say marriage is really difficult and you have to work at it, we never understand that saying ... and long may that continue. 

"I think that we are happy anyway but since 'X Factor' maybe happier." 

Robbie also heaped praise on his 39-year-old spouse, suggesting she feels "more fulfilled" now than ever before. 

The 'Love My Life' hitmaker - who has kids Teddy, six, Charlie, four, and three-month-old Coco with the actress - said: "Ayda's ambitious and talented and creative and I dragged her away from her job and made her be my dressing room support. 

"Now she has been working and really enjoying herself and because she is more fulfilled I guess that as a unit we are happier." 

Despite enjoying his time on the show, Robbie wants a pay rise if he is to return to 'The X Factor' in 2019. 

Asked whether he would be interested in returning for another series, he recently said: "We would love to come back. But we need to be treated kindly, so we'll see. Is that my pitch for a pay rise? Abso-f***ing-lutely."