Sting and Paul Simon are rehearsing for their upcoming tour, a couple of friends and neighbours preparing to take turns singing some of each other's biggest hits.

It was Simon's idea for the tour, hatched when he came downstairs in their New York apartment building to ask if Sting would be interested.

Of course, Sting told him, having first heard Simon & Garfunkel when he was a 15-year-old in England.

Sting says they are starting the process of selecting the setlist for the tour, which opens on February 8 in Houston.

He says Simon has asked him to sing Bridge Over Troubled Water, while Simon is eager to sing Sting's songs Fields Of Gold and Fragile.

They first sang together at a charity concert in New York last year, and Sting says he was surprised by how well their voices blended.

"He's the master," Sting said. "If I ever wanted to emulate a literary and literate songwriter, then Paul Simon would be the person I would go to."