Robbie Williams and his wife Ayda Field have a ''unique relationship''.

The 43-year-old singer married the actress - with whom he has daughter Theodora, five, and son Charlton, three - in 2010, and has said that the pair are often outspoken about one another in interviews, as they like to ''one-up each other'' when it comes to the ''terrible things'' they say.

In Robbie's book 'Reveal', he detailed the first time he met the American actress, including revealing his inner thoughts where he criticised her weight.

But the star insists Ayda isn't offended by her spouses comments, as when asked if she cares about what he says, Robbie said: ''No, she doesn't - we've got a unique relationship in that way. We sort of like to one-up each other on the terrible things we say about each other.''

That isn't to say Ayda, 38, never gets angry with the 'Angels' hitmaker though, as Robbie admits their joint appearance on 'The Graham Norton Show' was a breaking point for her bottled emotions.

On the show, Ayda appeared during a red chair segment, where she was supposed to tell a story, and if host Graham Norton wasn't amused, he would pull a lever to tip her chair backwards.

However, as soon as she appeared on screen, Robbie decided to pull the lever himself, without giving her a chance to speak.

Speaking about the incident to NME magazine, Robbie said: ''That being said, I was on 'Graham Norton' last night and she did the red chair bit at the end. I pulled the lever as soon as she sat down and that, weirdly, was the thing that did it.

''All the other stuff, she's been fine about - and there is a lot of other stuff - but for some reason I came off 'Graham Norton' going, 'How well did I do?' She just looked at me and gave me a dirty look.

''I was like: 'Oh, the pulling of the lever?' 'A bit, yeah, that.' I thought she was going to power-hug me and I was going to high-five because it got a big laugh. But that chair goes back very quickly, let's just say that.''