Blake Shelton can't believe he's been dating Gwen Stefani for four years.

The 43-year-old country star will celebrate his four-year anniversary with Gwen in November, and has said it's ''shocking'' that time has gone by so quickly, as it feels like a ''blur'' to him.

He said: ''It's actually shocking that it has already been that long. It's kind of a blur. It still feels like it's pretty new to me. I guess it is, relatively. Four years isn't forever, but man, it seems like it just happened in no time.''

Blake will get to spend more time with his 49-year-old girlfriend Gwen later this year when she takes over from Adam Levine as a coach on 'The Voice', and although Blake will ''miss'' the Maroon 5 singer, he joked he's keen to have someone ''better looking'' on the panel.

He added: ''We're all going to miss Adam. There's no way around it. But [Gwen's] way better looking than he is, in my opinion.''

Gwen - who previously coached for three seasons of the singing competition - is already ''feeling competitive'' about her return, but Blake insists he won't be letting her walk away with one of her acts as the winner.

The 'God's Country' singer told People magazine: ''I'm glad that she's already feeling competitive. Of course, I'm not going to let her win. I'm going to have to win, but I'm going to have to do it in a way that she doesn't feel like I beat her. I don't know if that's possible or not because I definitely don't want to upset her - that's not going to pay off for me in the long run. This will be her fourth time on the show, so she's no stranger to it. She knows what she's doing.''