Former Eurovision Song Contest winning ABBA legends Benny Andersson and Björn Ulvæus have reportedly agreed to guest judge for music mogul Simon Cowel's hit talent show The X factor. They are reported to be appearing on the show for the semi final. The Swedish songwriters have been invited by the Pop Idol and American Idol judge to appear towards the end of the ITV series next month.

The two songwriters will be helping judges Simon Cowell, Sharon Osbourne and Louis Walsh decide who will make it through to the final and will then give finalists tips on their performances. An X factor source said yesterday: “This is a major coup for us. To get the guys who wrote ABBA's hits to be involved in our show is just amazing.

Benny and Björn starred as the male vocalists in the former Eurovision Song Contest winning band from 1972 until the group split in 1984. They were the masterminds behind the band, forming it and writing the vast majority of their songs. Since the group broke apart, they have continued to write songs, and created the Mamma Mia musical which has become one of the most successful stage shows of all time. It can currently be found in New York City's Broadway, London's Theatreland,and has been translated into many languages for performances around the world.

Their appearance marks a continuation of the theme for successful stage show masterminds appearing on British television. Andrew Lloyd-Webber recently starred as a judge on the BBC seriesHow do you solve a problem like Maria, in which women performed to win the right to play Maria von Trapp in the upcoming London stage production of 'Sound of Music'.

They are not the first EurovisionSong Contest link to the show, with 1997Great British Song Contest entrant Kerry McGregor, who sang Yodel in thecanyon of love, amongst the contenders for a place in the final 12 performers.