What is the fine-grained topic of the following text: Produced by Van Morrison along with Don Was and Bob Rock, the album features duet performances with Bobby Womack, Steve Winwood, Mark Knopfler, Taj Mahal, Mavis Staples, Michael Bublé, Natalie Cole, George Benson, Gregory Porter, Clare Teal, P.J. Only return the topic.
Duet performances in Van Morrison's album