Paul McCartney might be joining Elton John on stage at Glastonbury Festival this weekend.The Beatles legend was among VIPs who were spotted watching Foo Fighters side stage when the band performed their surprise set as mystery band The Churnups yesterday (June 23).However, festival-goers and watchers have suspected that Macca is down on the farm for another reason – to appear as John’s special guest when he performs in the Legends slot tomorrow (June 25).Back in December, John was confirmed as first Glastonbury Festival 2023 headliner, which will be the final UK show of the ‘Rocket Man’ singer’s last ever tour.He’s since revealed that he has developed a “brand new show” for his Glasto set.Rumours of potential guests first arose following a recent interview with John, in which he teased that some special guests would be joining him for during his closing headline set on Sunday.