The season 8 runner-up will also perform on the competition's May 19 finale.

American Idol is paying tribute to one of the most famous rock bands of all time in an upcoming episode. Each of the top eight contestants will perform a song from the Queen catalog, before partnering up for classic movie duets, and the fitting celebrity mentor for the week will be Adam Lambert.

Lambert has been touring as the frontman of Queen since 2011. Of course, Lambert and Idol go way back, as the singer performed "Bohemian Rhapsody" during his own audition for the show in 2009 and he later sang with the band in that year's season's finale before finishing as season 8 runner-up.

Viewers will also see Lambert another time this season, when he performs on the season 17 finale, airing May 19. Before that, the top eight will take on Queen with Lambert's help on April 28 at 8 p.m. ET on ABC.

The new incarnation of Idol is the first reality competition series on American television to allow viewers to watch and vote simultaneously. For this episode, viewers will be able to vote by text, via AmericanIdol.com/vote, and on the show's app during the show. Results will be revealed at the end of the show in real time, across all time zones.