Musician Nile Rodgers said he was "incredibly proud" of the surprise success of his number one hit Get Lucky with Daft Punk.
The Chic guitarist, headlining the West Holts stage at Glastonbury on Friday, said: "All the stuff happening with this record blew me away. As of yesterday (Thursday) afternoon, a million copies had sold in 69 days.
"I knew the record was good. But what's unexpected about it is the fact it got so big."
Daft Punk are strongly rumoured to be playing a secret set at the Somerset festival, even though that has been denied by organiser Michael Eavis. Some thought they may even appear on stage with Nile.
He said: "A ton of people have come up to me to talk about these rumours. But I'm just playing with Chic as far as I know."
He said of his recent hit: "I'm incredibly proud. But more than anything, I'm proud and happy for Daft Punk. That's who I was making this record for."
Before performing at his first-ever Glastonbury Festival, Nile took part in a question and answer session in the EE Garden. The invited guests included model Amber le Bon.
Nile, who has worked with David Bowie and Sister Sledge in his long career, told the audience he first met Daft Punk 17 years ago in New York.
"We agreed to get together at some point in the future. What I didn't know is that it would take 16 years," he joked.
Nile added that he was pleased it was not raining for his debut performance - as he was wearing white pumps rather than wellies.