Townshend told Xfm that The Who would be performing

However, he said the rock act were not the "biggest band in the world" he referred to in a recent BBC interview.

Mr Eavis confirmed The Who were poised to play after guitarist Pete Townshend told radio station Xfm that he and Roger Daltrey would be appearing.

"It's not 100 per cent sorted, but if he's telling people he's playing then we have to," he told BBC News.

His comments followed an earlier interview in which he confirmed the Arctic Monkeys and Bjork would perform at this year's event.

We're absolutely full to the gunnels - we haven't got any space left Michael Eavis

In another interview - with NME's website - he hinted that Canadian rockers Arcade Fire had also been added to the bill.

Speaking to BBC 6 Music on Wednesday, Mr Eavis said the "biggest band in the world" had contacted him about performing.

But on Thursday morning, he said the act he had been referring to was "a modern band" who had got in touch following the announcement that Kylie Minogue was too busy to appear.

Mr Eavis refused to be drawn further, though he reiterated his earlier denial that Irish band U2 would perform.

Music Week has reported that the band in question is the Red Hot Chili Peppers.

The Arctic Monkeys have been confirmed as a headline act

Mr Eavis said this year's line-up was "absolutely full to the gunnels". "We haven't got any space left," he continued.

Speaking on Wednesday, Townshend said The Who's headline appearance on Sunday 24 June depended on "whether or not they give me enough space to park my tent".

Tickets go on sale on 1 April following a pre-registration period in February.