The singer turned to his old friend and asked him to help put together a comeback album following a hiatus Buble took to be with his young son as he battle cancer, and Foster now admits it was the special project he was looking for.
"I'm really grateful to Michael for getting me back into the studio," David tells the Chicago Sun Times. "He's made some good records without me but I think we both realised this was the right time for us to get back together again. He's truly fearless when it comes to music. And he's not lying when he says he's a changed man. Imagine the emotional rawness he was able to draw on from the last few years."
And Buble is glad Foster took his call and agreed to produce his new album, "Love", which hits stores on 16 November.
"He told me flat-out, 'Michael, I'll never go back into the studio'," the singer smiles. "We talked about all the stuff I was going through, and David said that if he did go back in it would have to be for something natural and organic and beautiful. It should be about love - making the music you love, the songs you love to sing. In retrospect, that sparked something in both of us."
Foster is all about love these days after asking his singer girlfriend Katharine McPhee to marry him back in July.