Ellen Degeneres is never at a loss for words, but she sure got Gwen Stefani tongue-twisted when she started probing about the pop star's romance with The Voice co-star Blake Shelton.

"I thought it would be a good idea not to talk about Blake, to see what would happen," Stefani responds when Degeneres brings up the subject, the No Doubt singer's face turning the cutest shade of red.

Since Stefani was hesitant to open up about her relationship with Shelton, Degeneres started going through a slideshow of the couple, which brought laughs from the crowd.

Degeneres eventually got Stefani to open up about how the country star popped the 'big question' ... whether Stefani would be his mentor on season 10 of The Voice. 

"I wanna be on that show as much as possible," Stefani notes with a giggle. "I got so much out of it."

Of course, she got more than just a hunky boyfriend out of the deal, but Degeneres stepped in and made the 46-year-old singer blush before we could hear the rest of her answer.

The new couple has gotten pretty cozy lately — they were photographed very close together at high-profile pre-Grammys gala thrown by music industry icon Clive Davis on Valentine's Day. Stefani also admitted that her latest single "Make Me Like You" is about Shelton, and he even gets a little shoutout in the music video.

The couple has seemed very happy together after they made their relationship public this fall, shortly after both divorced their respective spouses.

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