In an interview with No Doubt in The Guardian (UK national newspaper) on the 15th Feb, Kanal the bassst said of Prince:

'He tells a story about Prince flying the band to Paisley Park to play one of his songs. When they arrived, it was Stefani alone who was ushered into the sudio, while Kanal, Dumont and Young ended up twiddling their thumbs outside. "We expected to work with him, but it didn't work out that way," he shrugs. But Prince did make up for it by prducing the Rock Steady song Waiting Room.'