Kanye West feels as though he's been married to Kim Kardashian for "500 years" - joking that marriage years work in the same way as dog years.

The 42-year-old rapper opened up about his relationship with the reality TV star, with whom he has four children, during an interview on The Late Late Show with James Corden on Monday night. While Corden is famous for his Carpool Karaoke segment on his show, the host switched things up with Kanye and the pair took part in Airpool Karaoke - where the British presenter took to the skies with the Yeezy mogul.

Among the topics covered during their wide-ranging interview was Kanye's marriage, about which he joked: "Marriage years are different than human years."

"Like you know how dog years are like seven years? Every marriage year is like 100 years," he laughed, adding he feels as though his five-year marriage has lasted "500 years".

Elsewhere in the interview, Kanye discussed his mental health issues, and credited God for helping him find his way.

He also dished on how, in his darkest moments, his family and friends were hoping he'd be OK, and had his best intentions at heart, but didn't know how to get through to him.

"People in my family were praying for me, but they couldn't call me and scream at me. I'm a grown man," he explained. "But it was God that came and put this thing on my heart and asked if I was ready to be in service to him... I have no regret and no shame."

While Carpool Karaoke usually sees Corden sing along with his celebrity guest and their songs, things were a bit different on Airpool Karaoke - with the passengers on the aeroplane made up of the choir from Kanye's Sunday Service. So when it came to performing the tunes, it was the choir who belted out some live music from the rapper's new Jesus Is King gospel record.