When My Chemical Romance and the Used collaborated earlier this year on a version of Queen and David Bowie's 1982 hit "Under Pressure," they had no idea they'd wind up inspiring Queen's label to kick-start a long-discussed Queen tribute album. But when the single debuted at #54 on the Billboard Hot 100, the staff at Hollywood Records started buzzing.

"It proved that a cover version of a Queen song could be a big hit," says Geoffrey Weiss, vice president of A&R at the label. "The combination of that and the fact that Queen were planning a tour made us go, 'OK, now's the time to do this.' "

Killer Queen: A Tribute to Queen comes out Tuesday and features 16 artists from a variety of genres, including R&B, pop, rock, punk, alternative and metal. Highlights include Jason Mraz doing "Good Old Fashioned Lover Boy," Shinedown tackling "Tie Your Mother Down," Joss Stone taking on "Under Pressure," Sum 41 nailing "Killer Queen," and "American Idol" contestant Constantine Maroulis and the Flaming Lips performing radically different versions of "Bohemian Rhapsody."

The Maroulis track, performed with the London cast of the Queen musical "We Will Rock You," is faithful to the original and similar to the one Maroulis performed on "American Idol" (see [article id="1501836"]" 'Idol' Covers Paying Off For Gavin DeGraw, Los Lonely Boys"[/article]). The track will be the first song on the disc to go to radio. The Flaming Lips' take on the tune, by contrast, is more haunting and textural, filled with layered keyboard effects, wobbly guitars and demented vocals.

"We really attempted it in a full-force Flaming Lips behemoth production style," singer Wayne Coyne said. "We recorded 100 tracks of our beloved pedal steel guitar and 100 guitar overdubs for the music, and for the vocals we stacked all these crazy harmonies. We wanted to add different layers that people might expect from us, but we tried hard not to change the fundamental nature of the song."

About a week after the Flaming Lips submitted their version of "Bohemian Rhapsody" Weiss got a call from Constantine's management saying he was interested in performing the track for the record, and because of his mainstream visibility, Weiss gave him the thumbs up. "I thought having the two versions is kind of poetic as well," Weiss said. "That the same Queen song can appeal to everyone from 'American Idol' to the Flaming Lips speaks a great deal about the range of the band's music."

Weiss started hunting down acts for Killer Queen in November and within weeks had generated a strong roster of musicians. Gavin DeGraw was the first to hand in a song, submitting his soulful version of "We Are the Champions" in January. Others took far longer. Joss Stone and Jon Brion turned in "Under Pressure" and "Play the Game," respectively, in June as the album was being mastered, and Antigone Rising, who did "Fat Bottomed Girls," didn't finish the legal paperwork until the last minute. Then there was Macy Gray, who finished recording but didn't complete the contract forms in time, and had to be left off the album.

"When you're going after artists who have careers and are working hard, it's not anyone's number one priority to contribute to a tribute album, and we didn't have years to do it," Weiss said. "So dealing with timetables and working around people's schedules was the biggest problem."

Fortunately, many felt such a kinship with the project that they found time for it. And, because of their immense respect for the material, most of the artists went above and beyond to live up to the challenge. Jason Mraz, for example, layered delicate piano, bobbing bass, gliding strings and mellifluous vocal harmonies for his take on "Good Old Fashioned Loverboy."

"To me, Queen represented real variety as well as world-class professionalism," he said in a statement. "They were the musicians' musicians, and because of their insight, they were often seeing their finely detailed recordings soar over the heads of their listeners, because in essence what they did was perfect."

Sum 41 worked hard to capture the drama, dynamics and heaviness of "Killer Queen," but perhaps the most impressive aspect of their performance is Deryck Whibley's spot-on sophisticated vocals, which are a major departure for the pop-punk prankster.

"The biggest impact Queen has had in our music is structure of songs," he said in a statement. "They've always had crazy structures, but still the songs have great flow. It proves that [a song] doesn't have to be typical to work."

Other songs on Killer Queen include "Stone Cold Crazy" by Eleven with Queens of the Stone Age frontman Josh Homme, "Death on Two Legs" by Rooney, "Who Wants to Live Forever" by Breaking Benjamin and "Bicycle Race" by Be Your Own Pet.

On September 13, about a month after the release of Killer Queen, Queen will release the double live CD Return of the Champions, which was taped during their May 9 performance in Sheffield, England. A DVD of the set will follow on October 24. Both releases feature vocalist Paul Rodgers (ex-Bad Company) and include at least one new song. Between tours of Europe and Japan, Queen will play two shows in the United States: October 16 in East Rutherford, New Jersey, and October 22 in Hollywood.