ET's Nischelle Turner spoke "Ol' Red" singer at Saturday's premiere of UglyDolls in Los Angeles, where he joked that his role in the animated movie is doing wonders for his relationship with 12-year-old Kingston, 10-year-old Zuma and 5-year-old Apollo.
"My cool points are going up a little bit with the kids, which I need all the help I can get," he cracked.
According to Shelton, Stefani's kids "know way more about this movie than I do."
"They're like, talking to me about scenes that I haven't seen. I was like, 'Where'd you see that?' 'Oh, it's on the internet, you tweeted it!'" he explained. "It's like, 'I did? What are you talking about?' So, they've been looking forward to it for a long time."
"There's one scene that Apollo, the youngest, has watched already about 30 times. It's on the trailer," Shelton said. "It's already fascinating to him."
Apollo also appeared to be channeling Shelton's signature style at Saturday's premiere -- mixed with a little influence from his famous mom.
"Look at that! He's got his cowboy boots on, his jean jacket, but then he's got a little leopard print," Shelton shared. "Thank God one of the guys in this group has some style."
The Voice coach plays Ox, the Unofficial Mayor of Uglyville and a mentor to all of the other UglyDolls in the movie, based off the toys of the same name.
"It's a long fall," Shelton joked about going from the Sexiest Man Alive to the Unofficial Mayor of Uglyville. "I think this [title] is probably more appropriate than the other one was to begin with, but I got to say, I don't know who all is involved in the movie. I've only worked with the directors and a couple of the producers, but whoever wrote this script, it's such a great message.
"It's a great message for kids, it's a great message for adults too," he added.
The singer may still be getting used to voice acting -- "It's so weird [to be called an actor]," he admitted -- but he said he's already heard some good reviews.
"I'm gonna walk in and see it for the first time and I'm excited. I've got some good reviews from these people who saw the movie already, so that's good," he shared. "I don't know what to expect."
Though Shelton didn't know what to expect from the film, he, Stefani and the kids appeared to have a great time. An eyewitness tells ET that Apollo didn't leave Shelton's side all day, with the two spending some quality time together away from the rest of the group, going on rides and doing activities together.
UglyDolls hits theaters on Friday. See more on Shelton in the video below.