Children’s doctor Katie Rogerson, who comes from Roundhay, is part of the Lewisham and Greenwich NHS Choir which opened the Pyramid Stage on Saturday.
Their performance came exactly six months after they scored a Christmas number one with their single, A Bridge Over You.
Festival-goers with NHS banners stood at the front to support the choir, who began their set with Bill Withers’s Lean On Me. Many of the singers were in tears afterwards.
Glastonbury organiser Emily Eavis had invited them to perform after talking to NHS staff about the impact of cuts when she had a baby.
Joe Blunden, an NHS communications manager, said: “We thought it was a joke at first. It just came through on social media, and we thought, this can’t be real.
“And then before you know it, we’re standing on the Pyramid Stage, and it’s ridiculous.”
The choir have just released their debut album, Something Inside So Strong.