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Blake Shelton is a country star, television coach and all-around good guy, but one things fans wouldn’t expect him to add to his resume is personal trainer.

But girlfriend Gwen Stefani jokes the country star is her very own trainer who encourages her stay fit.

Related: Gwen Stefani: My Sons Love Blake Shelton

“Actually, it’s because of [Blake] that I worked out this morning,” Gwen revealed in a Facebook Live interview with Entertainment Tonight. “I wasn’t gonna work out... He’s my trainer.”

Blake once told Cody he “goes through phases” in his exercise journey.

“I actually bought a treadmill and had it delivered to my house in Los Angeles, and they set it up,” Blake revealed exclusively, “and I think I ran on it that day because I was pumped about it that day for about 15 minutes. And it hadn’t been touched since then.”

Related: Gwen Stefani Updates Twitter Pictures to Blake Shelton Throwback

The “Every Time I Hear That Song” singer tells ET “it’s not fair” how easy it is for his No Doubt girlfriend to stay in shape.

“I mean look at [her],” Blake says of Gwen. “Wouldn't you like to be born with her genetics?”

Watch the couple on The Voice Mondays and Tuesdays on NBC.