The 38-year-old singer has been at the centre of rumours she may have had a cleavage augmentation for the past couple of years. But as Louis, who appears with Nicole as a judge on U.K. talent show The X Factor, filmed an appearance on British TV programme Celebrity Juice, due to air on Thursday night (03Nov16), he let the Pussycat out the bag when he admitted his pal had gone under the knife.

The celebrity panel were playing a game called "What's the craic" when somebody commented on Nicole's boosted cleavage. At that point, Louis jumped in and said, "Yes, they're new boobs! She has new boobs!”, according to Britain's Daily Mirror newspaper.

The audience member who reported the revelation added that Louis "didn’t seem to be joking".

Nicole has previously denied she had given her breasts a surgical boost, putting her curvier figure down to better bras during an interview in 2012.

"Everybody can have cleavage with the bras we have today," she said. "And I use those bras – absolutely. They can give you confidence!

"I haven't had cosmetic surgery. But maybe I would, in time. I’m not against it, if you want to enhance something or make yourself feel a little bit more confident. To each their own."

Louis' revelation comes after Nicole opened up to InStyle magazine about her relationship with 25-year-old tennis player Grigor Dimitrov, admitting that while she sees marriage and children in her future, she's in no rush.

"A few years down the line, yeah, it’s something that I’m going to be thinking about," she told the publication. "I feel like I haven’t scratched the surface of what I’m supposed to do and create, and that’s where my mind is at. So when I’ve got there, and it’s the right time, then maybe I’ll think about kids and a family."