Blake Shelton admits his relationship with Gwen Stefani is "odd".

Speaking on 'Today', he said: "It's a little weird. We could not be, on paper, any more different. I mean, I'm a country singer and she's a ska, rock, pop, whatever it is ... and it's just an odd idea. But man, it's a lot of fun. I've gotta be honest about that."

The couple recently worked together on a duet, 'Go Ahead and Break My Heart' and Blake initially started writing the track to "impress" Gwen, 46.

He admitted: "I actually wrote that song, started it just to try to impress her, to be honest with you.

"I sent it to her just half done and said, 'I wrote a song, kind of about you,' and she wrote the next verse and sent it back to me. And so it was like, 'Oh, we've got a song together.' That's kind of cool."

The singer's new album, 'If I'm Honest' is largely inspired by his personal upheaval and he admitted he made a conscious decision to "cash in" on his life because there have been so many stories about him and his situation.

He said: "I figured because everyone else is cashing in on my life, I might as well too. So, that's what the record is."

Gwen - who has sons Kingston, nine, Zuma, seven, and Apollo, two, with Gavin - has previously admitted she never expected to fall in love with Blake.

She has said: "[He] had been going through literally the exact same thing in literally the exact same time frame.

"Never in my wildest, craziest dreams would I ever have seen this coming."