KEVIN FEDERLINE won't let Britney Spears put their son Sean Preston on stage in Las Vegas.

The singer's ex-husband - who was married to the 'Toxic' hitmaker from 2004 to 2007 - was less than impressed when he heard Britney was planning to have their eldest child join her during her two-year concert residency, 'Piece of Me', at the Planet Hollywood Hotel and Casino the gambling capital.

Quizzed by a TMZ reporter as to whether he would let the seven-year-old boy perform, Kevin said: ''I mean ... we'll see about that, won't we.''

Sean and Jayden, six, joined Britney in her new video for the 'Smurfs 2' soundtrack single, 'Ooh La La', and it appears the elder of their two sons has developed a taste for the limelight.

However, Britney feels Jayden would be too shy to take to the stage.

Probed further if he would like Sean to perform, the boys' dad Kevin scoffed: ''Yeah, if he was like 25 years old.''

The wannabe rapper - who tied the knot with his long-term girlfriend Victoria Prince earlier this month - was dismissive of Britney's shows in general, which kick off on December 27.

Kevin joked he had no intention of ever heading to Vegas to watch his ex's rumoured $310,000-a-night performances, and would only visit the US gambling capital for some serious casino action.

He scoffed: ''Nah man. Not my thing. When I'm in Vegas, I'm at the craps tables.''