John Legend has admitted it was ''truly a surprise'' to conceive his unborn third child naturally.

The 'All of Me' hitmaker and his model spouse, Chrissy Teigen - who welcomed daughter Luna, four, and Miles, two, via IVF - are having a baby boy and never expected to ''conquer'' the past ''fertility challenges'' they experienced.

In an interview with Cosmopolitan UK, John admitted: ''It was truly a surprise. We had struggled to conceive naturally all this time and figured it would never happen. I guess all of our time spent at home together was enough to conquer any fertility challenges we had. We thought it couldn't happen this way and were worried that something would go wrong but, so far, all the tests have come back great and we feel very good.''

Since becoming a father, the 41-year-old singer has made sure to prioritise spending quality time with his brood.

On how fatherhood has changed him, he said: ''It gives you a sense of purpose greater than yourself. You can help influence the next generation and they can make the world a better place. It makes you think about work priorities. As soon as we had Luna, I thought more about my work schedule and how much I wanted to be home. It's a different kind of love. You feel love for them because they're yours, but you feel this responsibility for them as well.''

And the 'Ordinary People' hitmaker admitted that whilst his kids love having both their parents at home amid the coronavirus pandemic, he's itching to get back out on the road.

He said: ''We're spending a lot of time with each other and that means our kids are in heaven. Their ideal situation is to hang out with us all day, every day. A downside for me is that we had to cancel my tour. I've released a new album and want to be out there performing the songs to people.''

John also revealed that he and Chrissy, 34 - who tied the knot in 2013 - have benefited from having couple therapy every now and then.

On what the key to their successful marriage is, he said: ''It sounds obvious, but being with someone you really care about, respect and enjoy being around. I think that's the crucial foundation. Then communicating, being considerate, listening to your partner and making sure their needs are met. And we go to therapy sometimes. I think every couple who has been together for a long time could use time to talk with a third party to help with whatever concerns they have.''

Read the full interview by heading to www.cosmopolitan.com/UK/JohnLegend.