The 42-year-old singer and television personality got a nudge to propose to Stefani, his girlfriend of over three years, during his visit to the talk show Wednesday.
"So, Mother's Day is coming up. I have something for you to give her," DeGeneres told Shelton.
"So you're saying there's a chance she's going to ask me to marry her?" Shelton responded. "See how I flipped it around and put it on her."
"Now that she knows that you're waiting for her to ask, now that she sees this, she'll ask you," DeGeneres said. "I'll call her tonight. I'll tell her she's waiting for you."
Shelton and Stefani confirmed their relationship in November 2015 following their respective splits from Miranda Lambert and Gavin Rossdale. The couple attended the premiere of Shelton's movie UglyDolls last week with Stefani's three sons and her brother.
"We went to the premiere of the movie ... I think my first scene and Gwen turns to me and goes, 'Is that your cartoon voice?'" Shelton shared. "I was like, 'I've only got one voice.'"
"We brought all the kids and actually Gwen's brother and his family, so we made a whole day out of it. It was a lot of fun," he said.
Shelton voices Ox in UglyDolls, which opens in theaters Friday. The movie is based on the plush toys of the same name.
"UglyDolls, it's got a great message. It's about these dolls -- as they're created, if they've got any flaws or anything that makes them different or is wrong with them, they kind of get thrown over into recycling. They've created their own community there and they don't realize there's anything different about them at all," Shelton explained.
"I don't want to give too much away, but it's got a great message. And there's so much music in it, which is why I was happy to be a part," he said.
Shelton shared a photo with his character on Instagram in March.
"Here's Ox, the mayor of Uglyville in @uglydolls, and the mayor of Ole Red working on last nights set list for @oleredgburg - Team BS," he wrote.