Foo Fighters could perform at Glastonbury Festival after the band were forced to pull-out of their Friday night headline slot.

The Glastonbury rumour mill has started to spin with speculation that the band could appear as 'secret guests'.

According to one insider, the band are lined up to performed a "chilled out acoustic set" after frontman Dave Grohl broke his leg during a concert in Sweden two weeks ago and Florence + the Machine were brought in to replace them.

As tens of thousands of ticket-holders started to set up camp on the Somerset site today bookies began to take bets on a Foos appearance.

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"There are always so many rumours in the build up to Glastonbury and if anyone is to make a shock appearance, the organisers have done very well," William Hill spokesman Joe Crilly said.

"The odds suggest that Bastille, Foo Fighters (with a sat down Dave Grohl) and Taylor Swift could all make appearances."

The bookmakers are also taking bets on who will appear alongside rapper Kanye West during his Saturday headline slot.

News that the controversial hip hop artist had been booked to headline was met with a backlash by Glastonbury fans, so the pressure will be on to deliver a legendary show. Sir Paul McCartney is currently on Even money to perform alongside West, while long-time collaborators Jay Z (4/1), Rihanna (3/1) and Beyonce (6/1) are also in the running.

After suspending betting on London indie band Bastille making a surprise appearance, William Hill have now been forced to cut the odds of last-minute Blur set from 12/1 to Even.

Other musical highlights at the festival include Chemical Brothers, Rudimental, George Ezra, Motorhead, Lionel Richie, Alt J, and Paloma Faith.