Smokey Robinson is one of the guest stars on "Soulbook," which features Stewart singing some of soul music's most revered tunes. It follows in Stewart's trend of recording classic covers (he had a resurgence with his "Great American Songbook" album series).
In an interview, the Rock and Roll Hall of Famer said he was elated to sing "Tracks of My Tears," which Robinson recorded with the Miracles decades ago on Motown, with the legendary singer and composer.
"I grew up listening to Smokey Robinson to have that guy come into the studio and sing on 'Tracks Of My Tears' (was great)," he said.
Stevie Wonder also joined Stewart to sing one of his signature songs, "My Cherie Amour," another highlight for Stewart. Even calling Wonder on the phone turned out to be a treat for Stewart.
"When you phone Stevie up ... he sings his answer. He goes (sings) 'Hello. I'm not in today but if you like to leave a message ... call me back,' He does this great thing, so I phoned him back and (sang) 'Stevie, thanks for playing on 'My Cherie Amour,"' Stewart said. "And when he had done 'My Cherie Amour,' he left me a message at the end of the track said, 'Rod, I am so thankful I was able to play on your track on my song. May the good lord be with you.' Such a sweetheart."
The CD also features appearances by Mary J. Blige and Jennifer Hudson. "Soulbook" was released in October. Now that Stewart has taken on soul music, he's willing to take other genres, even the blues.
"I would love to sing all that stuff. I really would. It could go on and on and on," he said. "The one thing I won't be doing is I won't be writing any songs. It has gone past me now, the writing phase. It was always a struggle."