David Foster says his romance with Katharine Mcphee is ''challenging in the best way possible''.

The 70-year-old musician recently celebrated his first wedding anniversary with Katharine, 36, and has now heaped praise on his spouse as he described her as ''super-talented'' and ''super-evolved''.

He said: ''We're doing great. She's opinionated, super-talented, and along with that super-talent comes a big brain, and she's got a lot to say. It's challenging, but in the best way possible.

''She has to keep pushing to make me answer things that I don't want to answer, which is great. Her navigation skills are better than anybody's I've ever seen and she's super-evolved.''

The 'David Foster: Off the Record' star also gushed over Katharine's ability to ''float in and out of the family dynamics'', as she's had the stamp of approval from David's children from previous relationships - Allison, 50, Amy, 46, Sara, 39, Erin, 37, and Jordan, 33.

He added: ''She's really magical and able to float in and out of all the family dynamics. It's amazing to watch because that's a huge talent - being able to navigate my life.''

And whilst the producer wouldn't comment on the possibility of expanding his brood further with Katharine, he did suggest they could collaborate on music in the future.

Speaking to Us Weekly magazine, he said: ''I think maybe we should make a record together. I would love to and I think she would love to, and I think it would be really a cool thing to do. She has a great voice. We could make a great stream.''

David's comments come after he and the 'Scorpion' star recently described each other as the ''loves of [their] life'' during sweet tributes to mark their anniversary.

Katharine wrote on social media: ''A year ago today I married the love of my life. Thank you for always loving me and inspiring me in all aspects of my life. I love you. Here's to the future! (Oh and happy anniversary to the other love of my life - this dreamy dress! (sic)''

Whilst David wrote in his own post: ''happy anniversary to the love of my life!! (sic)''