"I think that we couldn't be more different," Brad Paisley tells PEOPLE of his fellow panelist – and new friend – Ludacris. "But we're thick as thieves. It's one of the fastest friendships I've ever made."
Not even losing an expensive bet could deter Paisley from singing the praises of his new pal.
"He's such a big star, a great actor and one of the most important and influential rappers of all time. He has earned the right to be sort of difficult, but he is so warm and brilliant," says the busy star, whose new album Moonshine in the Trunk will be available Aug. 25.
Rounding out Paisley and Ludacris's friendship is the third member of their Rising Star panel, Kesha.
"You'd imagine her to be foul-mouthed and hard-edged, but she's extremely sweet and kind," Paisley says of the singer. "I mean, she certainly can cuss a sailor under the table if she wants, but usually it is out of humor."
And don't think their friendship is just for the cameras, either.
"We will frequently get together after an entire day of working," Paisley says about Kesha and Ludacris, who made an impromptu decision to join the country singer at the Los Angeles premiere of Disney's Planes: Fire and Rescue on July 15. "We mentored all day and then they hopped in a limo with me and we walked the carpet together, just because we are buddies. Who would have thought?"
Rising Star airs Sundays at 9 p.m. ET on ABC.