Singer Adele reportedly turned down "millions" to record the “Spectre” theme song.

According to a source, the Grammy Award-winning artist - who co-wrote and sang the soundtrack for “Skyfall” in 2012, didn't reprise her singing duties for the forthcoming James Bond movie because it would be hard to beat her global smash, despite being the top choice of Daniel Craig, reports dailystar.co.uk.

“Adele was James Bond himself's first choice. Daniel Craig was really keen and (director) Sam Mendes was 50/50 over whether to use her or a fresh voice,” the source said.

“Filmmakers were prepared to offer millions but Adele was never up for it. How do you top a worldwide hit like 'Skyfall' any way? It was too big a risk,” the source added.

“Spectre” theme song, entitled “Writing's on the wall”, has instead been penned by singer Sam Smith.