Van Morrison had no idea Bobby Womack was so close to death when the two stars worked together in 2013, because the soul legend was too professional to let his illness affect their duet.

Morrison had been planning to record a track with Womack for years and he's glad he got the chance before the Across 110th Street singer passed away last summer (14).

He tells Rolling Stone, "I knew he wasn't too well, but he didn't show it on the day. He looked pretty good.

"When I suggested the song (Some Peace of Mind), he said, 'Yeah, I can relate to the lyrics'."

Morrison's Duets: Re-Working The Catalog also features collaborations with Steve Winwood, Chris Farlowe, P.J. Proby and Taj Mahal.