Brian's caused Kerry enough pain already.. fighting over the kids will send her off the edge; 3 am EXCLUSIVE.

Byline: JESSICA CALLAN

KERRY Katona blows a raspberry at the world... and perhaps sends a message to Brian McFadden.

But behind all the laughter of a girlie night out, the former Atomic Kitten star is battling a new heartache.

She is devastated after learning her estranged husband is to fight for custody of their two young daughters.

Kerry knocked back cocktails at the weekend after hitting the hotspots of her hometown of Warrington, Cheshire.

She even snogged a mystery man and, appropriately enough, belted out I Will Survive on the Karaoke.

But friends said the 24-year-old singer, who is still being treated for depression at the Priory in London, is in turmoil.

A source said: "Brian has only just decided he is going to go after custody.

"He has caused Kerry enough pain already but fighting over the kids will send her off the edge.

"After he talked at the weekend about her sleeping with Dan Corsi, she decided to not get involved in a public spat. But, obviously, she is gutted."

Former Westlife star McFadden, 24, said last year he would not put Molly, three, and one-year-old Lilly Sue through a custody battle. But he now blames the split on Kerry's alleged fling with former boyfriend Dan in September.

Kerry, however, claims his affair with 20-year-old Aussie singer Delta Goodrem began before their marriage ended - and has branded him a "lying b***ard".

Her friends also believe McFadden did not realise there would be such a public backlash against him over Kerry.

Despite a successful start to his solo career last year, his tour plans have been put on hold while record chiefs wait to see how a duet with Delta does.

The source said: "Kerry is getting more and more sympathy. Brian has really rubbed her face in it about Delta."

Despite the setbacks in her personal life, Kerry, who last year won I'm A Celebrity, has seen her own career take off.

And she has just signed a deal with ITV to front a show called My Fair Kerry - in which she will learn deportment and etiquette from Austrian aristocrats.

Not that there were not too many aristocrats at the Chicago Rock Cafe in Warrington but Kerry still had a great time. A source said: "All the crowd were cheering when she did Karaoke.

"She said to them: 'I will survive. I spent ten days in the Priory for f**k sake'."

Brian beware.

CAPTION(S):

NEW LOVERS: Brian and Delta; BOY HAND: Lads help out Kerry during Karaoke night; KERRY-OKE KID; MAKING WAVES: She gets into spirit during YMCA; SUP{PORT ACT: Kerry and a pal get it all off their chest; POKING FUN: She leaves club after night out; EXCLUSIVE PICTURES: Mercury Press