Watch Adam Lambert Challenge James Corden to Queen Sing-Off

Brian May and Roger Taylor provide music after late-night host brags he'd be better Queen singer than former 'American Idol' star

James Corden and Adam Lambert had a 'Late Late Show' showdown to see who should be Queen's singer, with Brian May and Roger Taylor judging.

On the heels of Queen + Adam Lambert announcing a summer tour, James Corden and the former American Idol singer had a Late Late Show showdown to see who should serve as the band's vocalist.

"In my head growing up I thought that I would always make a great frontman for Queen," Corden told the audience. "I'm not saying I would be a better frontman than [Lambert]; I'm just saying I would be a better frontman than him."

Lambert then emerged from backstage to challenge Corden to a sing-off to see who should be fronting Queen. Waiting onstage were Queen's Brian May and Roger Taylor, who fired off a medley of Queen tracks for Lambert and Corden to sing along to.

Lambert first sang "We Will Rock You," which the late-night host deemed as "amateur hour." Corden then delivered "Don't Stop Me Now," a compelling performance that made Lambert so threatened that the singer cut it short. "Look at [May's] face, he knows he made a mistake," Corden bragged after his version.

However, after Lambert blew the audience away with "Another One Bites the Dust," an emotional Corden finally admitted to Lambert, "Okay, okay, you're a better frontman than me."

After calling a truce, the two ended their showdown with a "Somebody to Love" duet.

In a recent interview with Rolling Stone, Lambert opened up about filling the role once held by Freddie Mercury.

"What I always loved about Queen was that I could see what Freddie and the band were exploring, and I could identify with that," Lambert said. "I started falling in love with rock & roll, I dressed up like a club kid and went out at night, wore weird shit, I'm gay – all of that stuff put together. When I look at the history of rock & roll, Queen is the band that resonated the most with me… I've always been honored and understanding of the weight and legacy of the band."

Queen + Adam Lambert plot U.S. summer tour.