Blake Shelton Opens Up On His Romantic Christmas Duet With Gwen Stefani (Exclusive)

The 'Voice' coach opens up about singing with his girlfriend on her new holiday tune, 'You Make It Feel Like Christmas.'

Blake Shelton and Gwen Stefani's powerful romance is fueling their heartfelt holiday tune.

The couple's new collaboration, "You Make it Feel Like Christmas," -- recorded by Stefani, and featuring heartfelt vocals from Shelton -- paints a picture of Wintertime love and romance, and the angel-voiced pop singer has given a lot of credit to her country crooner boyfriend for help with the lyrics.

However, Shelton tells ET that he doesn't really deserve his ladylove's accolades.

"I sent Gwen a couple of lines of the song. She took it and made the song what it is. I just sent her an idea," Shelton humbly explained to ET's Lauren Zima on the red carpet at this week's taping of The Voice in Los Angeles. "She tries to say that I co-wrote it, but I just sang on it."

A few of the lyrics that stuck out for a lot of fans were the especially sweets lines, "I never thought I'd find a love like this/But I found forever in that very first kiss," and ET had to know if they were written about Stefani and Shelton.

"I would like to think so, come on," the 42-year-old Texoma Shore singer said, smiling. "This is romance around here, of course!"

While Shelton played coy about whether or not he considered Stefani his personal "forever," he couldn't help but gush over how stunning his sweetheart looked in the music video for their Christmas tune.

"How gorgeous does she look in that video?" Shelton's Voice co-star Jennifer Hudson said, joining Shelton on the red carpet.

"How gorgeous does she look all the time? It's unbelievable," Shelton replied. "Right now, wherever she is, she looks gorgeous, whatever she's doing."

As for their Shelton and Stefani's own Christmas plans, the country star said he knows for a fact that they will be doing something, he just has no idea what that might be, and he's OK with that.

"She normally just tells me what we're doing," he admitted. "So, I couldn't tell you what they are, yeah, [but] just wherever she is, I'll be there."

Check out Shelton and Hudson, along with fellow coaches Adam Levine and Kelly Clarkson, as season 15 of The Voice continues Mondays and Tuesdays at 8 p.m. ET/PT on NBC.