Gwyneth Paltrow may join husband`s band onstage for New Year`s Eve gig

Despite being famously cautious of being seen together, Gwyneth plans to show off her new musical skills when Coldplay play a $25million extravaganza in Las Vegas, according to US reports.

And the couple's best friends Jay-Z and Beyonce will also make an appearance together, according to the New York Post.

Coldplay and Jay-Z have each been paid up to $1million to perform for 2,500 invited guests at the new hotel new Cosmopolitan hotel in Vegas, according to the paper's Page Six column.

Andrew Fox, CEO of newyearseve.com, which sells event tickets, said: 'To my knowledge, this is the biggest spend on New Year's Eve - $25million over the weekend for 4,000 guests.'

Gwyneth stunned music industry insiders with an amazing performance at a recent awards show, and is proud of learning to play guitar for new movie Country Strong, in which she plays a country music superstar.

However, a spokesperson for the Cosmopolitan insisted: 'Gwyneth and Beyoncé are not confirmed for any kind of performance at this point.'

Paltrow's spokesperson did not return calls for comment.