Watch T.3 Go 'Into the Unknown' With Their Sky-High Notes on 'America's Got Talent'

Trae Patton/NBC

T.3 on "America's Got Talent"

The casually dressed trifecta of T.3 might have looked unassuming when they hit the stage on Tuesday night's (June 15) America's Got Talent, but they caught everyone's attention as soon as they started singing.

Liam, Brendan and Jim are a trio of tenors, but this is definitely not The Three Tenors from the '90s. Instead of opera arias, T.3 tackle sky-high pop songs -- like "Into the Unknown" from Frozen 2, which was performed by Idina Menzel, featuring Aurora, in the blockbuster Disney sequel.

Each of the men reached for the rafters with their wails in the song, with host Terry Crews marveling, "That sound was big!" After the performance, they got a standing ovation from all four judges -- Howie Mandel, Heidi Klum, Sofia Vergara and Simon Cowell --  who could barely hide their surprise at the trio's giant sound.

The guys have only been together as a group for a little over a year, meeting up when Brendan DM'd Liam and Jim after seeing some of their YouTube videos. Now, they've brought their act from Brendan's parents' staircase to the AGT stage.

"Do you think what you have to offer is worth $1 million and winning here?" Mandel asked before they started singing. Well, judge for yourself with the performance below. America's Got Talent airs Tuesdays at 8 p.m. ET on NBC.