'The Voice': Blake Shelton Credits Gwen Stefani with Helping Him Cope in the Absence of Adam Levine

Monday night (Sept. 23) marked the first time The Voice aired without longtime coach Adam Levine [...]

Monday night (Sept. 23) marked the first time The Voice aired without longtime coach Adam Levine sitting in one of the four red swivel chairs. While Shelton is still getting used to Levine's absence, he credits his longtime girlfriend, Gwen Stefani, who took Levine's place, with helping him get used to filming the reality TV talent show without Levine.

"I've been here for a hundred years," Shelton told PEOPLE. "She's been on the show; this will be her fourth [season]. It feels normal to have her back, but at the same time, it's exciting. And at the same time, it kind of helps the weirdness of Adam not being here. To be honest, it's strange to not have him here ... He's never not been here.

"He's that guy that's over there making you constantly want to strangle him, and now he's gone," he added. "It sucks, to be honest with you. But having Gwen back, for me, makes it a lot more fun."

Kelly Clarkson, who is also returning for her fourth season as a coach on The Voice, is now seated in the place that belonged to Levine for the first 16 seasons, joked that Clarkson is the reason Levine decided to leave.

"But they put you in his chair and that's kinda like the symbolism," Shelton joked.

"I think they put me in his chair because you dislike me as much," Clarkson retorted. "So, I think they're like, maybe if we put her there, he'll be as hard on her as he was on him."

Shelton previously opened up about Stefani's return, insisting he was still going to compete with her just as much, in spite of their romantic relationship.

"I'm glad that she's already feeling competitive," Shelton told PEOPLE. "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."

The Voice, which also includes coach John Legend, airs on Monday and Tuesday nights at 8 p.m. ET on NBC.

Photo Credit: Film Magic / Gabe Ginsberg