There's a very good reason the [article id="1610708"]"American Idol" top four[/article] didn't mess around very much with the arrangements of the classic-rock songs they performed on Tuesday night: a) they probably weren't allowed to and, more important, b) these songs are really, really hard to sing as is.

Take, for example, Milwaukee native Danny Gokey's choice of [artist id="1028"]Aerosmith[/artist]'s "Dream On." The prototype for all hard-rock power ballads that followed, the song is from the Boston-bred band's 1973 self-titled debut album. It mixes sensitive piano playing with a string section and fuzzed-out, distorted guitars for an emotional roller-coaster that made then-25-year-old lead singer Steven Tyler sound like he'd already lived the life of an 80-year-old blues originator.

(Read the story behind [article id="1610709"]Adam Lambert's rendition of "Whole Lotta Love" here[/article].)

Worship leader Gokey added some of his patented patina of gospel grit to the song, whose lyrics portray the hard drive necessary to follow your dreams and become somebody. It opens with Tyler lamenting, "Every time that I look in the mirror/ All these lines on my face gettin' clearer/ The past is gone/ It went by like dust to dawn/ Isn't that the way/ Everybody's got their dues in life to pay." By the time he reaches the triumphant chorus, Tyler's voice is seemingly energized, as he belts the lines, "Sing with me, if it's just for today/ Maybe tomorrow the good lord will take you away/ Dream on, dream on/ Dream yourself a dream come true/ Dream on, dream on/ Dream until your dream come true."

Gokey bravely dared to try the cat scratch yelp that Tyler unleashes in the song, with, admittedly, mixed results.

"Dream On," which Tyler began writing while still a teenager in the late 1960s, was released as Aerosmith's first single in 1973. It achieved minor hit status as it climbed to #59 on the charts upon its initial release and made it to #6 when it was re-released in 1976. Tyler plays the lyrical piano line in the song, which made it to #172 on Rolling Stone magazine's list of the "500 Greatest Songs of All Time" and is included in the Rock and Roll Hall of Fame's list of the "500 Songs That Shaped Rock and Roll."

Given its iconic status as one of the long-running group's signature songs, many artists have taken a shot at covering "Dream On," including metal maniac Ronnie James Dio, Tori Amos, Anastacia and Breaking Benjamin. "Idol" season-seven finalist Michael Johns performed it on the show, and Brooke White included it on her Songs From the Attic album, released before she appeared on the show.

The tune has also served as raw material for a number of rap acts, most notably Eminem, who used it as the basis for his ballad "Sing for the Moment," from his 2002 The Eminem Show album; the track featured Aerosmith guitarist Joe Perry playing a solo. Rapper Slim Thug also sampled it for his song "Rockstar," and The Game used it as a bed for his mixtape tune "Never Be Friends."

"Dream On" remains one of Aerosmith's most popular songs, and the instantly recognizable intro can still be heard blasting from classic-rock stations across the country, and the world, more than 30 years later.

Get your "Idol" fix on MTV News' [article id="1486475"]"American Idol" page[/article], where you'll find all the latest news, interviews and opinions.