Is Lady Gaga doing a secret DJ set at the Glastonbury festival?

Lady Gaga could be making an appearance at the Glastonbury Festival on Sunday. She's reportedly been seen around the Worthy Farm site already this weekend. According to The Sun, the Pokerface hitmaker wants to join Ronson's DJ set With Tame Impala's Kevin Parker at the Shangri-La area.

A source told the tabloid newspaper: "She's been saying to Mark for ages that she wanted to come to Glastonbury again. Mark is playing officially in the early hours of Sunday morning but they are trying to make another set work because she is due back in the States to meet the Dalai Llama on Sunday."

Ronson posted a snap of someone who looks suspiciously like the singer-songwriter on Instagram. It was captioned simply "Illusion": a cheeky hint Gaga's appearance was a trick of the eye perhaps?

The pair have been friends since Ronson, Gaga and Parker took to the studio last month to work on Gaga's forthcoming LP.

It would be Gaga's first Glastonbury appearance since she made her debut on the main stage in 2009, supporting Bloc Party and The Ting Tings on the Other Stage.

Meanwhile, Muse kicked off the festival's impressive trio of headliners on Friday, 24 June, which included Coldplay, with an extraordinary two-hour set. Muse opened their set with Psycho, a hard anti-war song from their current album, Drones – a concept record about modern warfare, and soldiers "who kill by remote control".

Although the band's recent shows have featured actual drones flying over the audience, according to BBC, they were refused permission to use them at Glastonbury. The group are usually compared to Queen because of their multi-layered vocals and cod-operatic tendencies. But like Queen, everything that makes Muse faintly ridiculous on record works to their benefit in front of such a huge audience.