Blake Shelton has found it ''shocking'' not working with Adam Levine on 'The Voice'.

The 43-year-old country star is still adjusting to life on the panel without his friend and admitted it has been very ''weird'' shooting the talent contest without the Maroon 5 frontman.

He said: ''Adam's not on the show and I want him to know that he can still kiss my ass wherever he is right now.

''Literally, you know, with Adam being gone, I'm not gonna lie, that was scary. It's weird. Without him here, it's literally shocking to not have him here.''

But without Adam, Blake's girlfriend Gwen Stefani has stepped in and rejoined the panel and he ''couldn't be happier'', even though she brings out his competitive side.

He told 'Entertainment Tonight': ''I couldn't be happier that she's back on the show.

''You know, she wants to win and I want to win and that's what they pay us to do on this show is to try to win the show.

''It's harder for [Gwen]. She's not, she's not competitive. She'll be the first to tell you right up until it gets competitive and then all of a sudden she is.''

The No Doubt frontwoman previously admitted it was ''bittersweet'' returning to 'The Voice' without Adam because he was the one who had encouraged her to sign up for her first stint.

She said: ''Adam was actually the first person to reach out to me when they were trying to pitch me the show.

''He texted me out of nowhere, and I didn't even really know him [back then]. And he was like, 'You got to do it. It's the greatest show. It's so fun!'

''So, to think that he's not going to be there is bittersweet. And plus, being between him and Blake and the amount of laughter - I would have to stop and massage my face because it would hurt!''