Blake Shelton is "more shocked" about his engagement to Gwen Stefani than anyone else.

Gwen Stefani and Blake Shelton

Gwen Stefani and Blake Shelton

The 44-year-old country star was dating the 51-year-old singer for five years before surprising everyone when he popped the question in October.

Discussing their engagement on 'The Late Show with Stephen Colbert', Blake said: "Nobody's more shocked about this than I am. It makes no sense. I can see that you're looking at that picture right now and thinking, 'What the hell is happening?'"

The talk-show host then held up the couple's photo announcing their engagement.

He quipped: "She seems happy about it! At first I thought it was a dare or something, she lost a bet. But she really seems happy here."

In response, Blake joked: "Bring it on, I can take it. I can take it. I understand. Trust me, I understand. You can't blame me for not jumping at the opportunity, though."

Blake made the confession shortly after the musician revealed people often question his relationship with Gwen after they starred in a Super Bowl commercial for T-Mobile.

Talking about the ad - in which Gwen is wrongly set up on a date with Blake after Adam Levine mishears her describing her ideal man - Blake admitted it was “so funny” to film because people often wonder “what happened to this world” to make the two of them fall for each other.

He said: "That’s what was funny about that commercial. Every day, if I look at social media or wherever, there’s always somebody commenting, going, ‘Man, what the hell happened to this world where Gwen Stefani and Blake Shelton are a thing now.’

"So we thought it’d be fun to have some fun with it."