London, Mar 04 : Pop star Britney Spears' ex-husband Kevin Federline is being paid 3,500 pounds a week to join her `Circus' tour in a bid to let her kids Sean Preston and Jayden James be by her side.

Ferderline, who has the custody of the two children, has accepted the offer to join the tour, which started on March 3.

"Kevin has custody of the kids and is being paid so they can be with their mum on the road," the Sun quoted a source as saying.

However, Ferderline is said to be ignoring the regulations attached with the offer.

According to reports, despite having joined the tour, he he was not by Britney's side with their children when the show began.

He instead was knocking down alcohol at a club, said reports.

"On Monday, when Britney was preparing, you might have thought he would have been at her side with the boys," the source said.

"Instead he spent the night in Harrah's Casino, hitting the blackjack tables and knocking back drinks with three pals," the source added.

Meanwhile, Britney looked great on stage with her military jacket and fishnet stockings, as she dazed the crowd with her incredible moves. (ANI)