"I don't know what he's thinking," Paisley tells PEOPLE

By Danielle Anderson
Updated November 19, 2015 12:00 PM
Credit: Trae Patton/NBC

Brad Paisley counts Blake Shelton as one of his close friends, and even though he hasn’t spent much time around Shelton and his new girlfriend Gwen Stefani yet, he already has an opinion.

“I do think she’s completely out of his league!” Paisley tells PEOPLE. “I don’t know what he’s thinking.

“I haven’t been around them since that news is out,” adds Paisley, who serves as a mentor on Shelton’s team on The Voice. “I’m going [to the show] Monday.”

As for how Shelton took his failed marriage to Miranda Lambert being the butt of a joke at the CMA Awards earlier this month, Paisley said Shelton “loved it. We basically just made fun of Blake, which is totally fair game at all times.”

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Paisley, 43, chatted with PEOPLE at the 3rd Annual Save the Children Illumination Gala in New York City on Tuesday, which he says he attended at the urging of another friend – Jennifer Garner.

“I was roped into this by Jennifer who is from my home state, we’re both proud mountaineers, proud West Virginians,” says Paisley. “A couple of years ago she contacted me and said, hey would you want to come see what we’re doing with Save the Children in West Virginia? There’s a school there that’s amazing that’s in a terrible area. It’s a spot where they’re working very hard to get these kids all the tools that they need.”

Paisley said he also makes sure to teach his own kids – Huck, 8 and Jasper, 6 – the importance of giving back.

“It’s all about exposing them to that and it’s a difficult thing when you are successful,” says Paisley. “So we’re really careful that they realize that there are people that don’t have the things that they have, and not only that, but don’t have the opportunities they have. They take it for granted that they can read any book they want to read and they go to a school where they’re loved and nurtured and they have parents that are there all the time. It’s an uphill battle but we really are trying to make sure they understand that.”