Blake Shelton and Keith Urban serve on the judging panels of competing reality singing shows. So, it's not just the contestants who battle on 'The Voice' and 'American Idol.'

Recently, the country heavyweights ignited a playful war of words, refereed (or ignited) by 'Access Hollywood.'

Urban had previously joked that he'd have to hire someone to fight Shelton, since ol' Blake is a bigger guy. When the playful show host brought Urban's words up during a separate interview with Shelton, the 'Mine Would Be You' singer responded with a riff on Urban's famously flawless coif.

Them's fightin' words.

Shelton's response to the notion of a "hitman" hired by Urban? He didn't answer directly, instead joking that Urban's hair is what would prevent him from doing the job himself.

"That guy better pack a lunch ... you know why I am not afraid?" Shelton asks. "Have you seen him perform? He really gets into it. I think he would get tangled up in his own hair."

"Like you can see Keith Urban if he got real mad and he was flailing around like he does?" he adds. "You know his hair would get in his face and mouth ... he’d be doing all that stuff. You'd clear a good smack in there or I'd just walk away."

Shelton kept it going, furthering that Urban doesn't even have enough money to hire someone to take him out!

There's another layer of "tension" between Shelton and Urban, since the latter duets with Shelton's wife Miranda Lambert on 'We Were Us' from his 'Fuse' album, which means that Shelton has to get along with him!

“I’m insanely jealous and I’m going into a jealous rage over this stuff. And that’s probably why he wants to hire somebody to kill me," Shelton says jokingly.

Boys will be boys. When is the Shelton-Urban duet? Soon, we hope!