Britney SpearsVia Jive / VevoBeyoncéVia Columbia / Vevo
Once upon a time in the year 2000, queen of pop Britney Spears was supported on her tour by a small group called Destiny's Child that was led by someone named Beyoncé Knowles.
Rascal FlattsVia Lyric Street / VevoTaylor SwiftVia Big Machine / Vevo
Ms. Swift actually supported Rascal Flatts on multiple tours between 2006 and 2008 before she went on to become the arena/stadium/universe-conquering force that she is today.
Aly and AJVia Hollywood / VevoMiley CyrusVia RCA / Vevo
Before Aly and AJ became 78violet (but after they blessed us with "Potential Breakup Song"), they opened for the Best of Both Worlds Tour, which featured performances from Miley Cyrus AND Hannah Montana!
The Jonas BrothersVia Jonas / VevoDemi LovatoVia Hollywood / Vevo
The Jonas Brothers
While Nick Jonas now seems to be the most popular of them all, he was once headlining concerts with his brothers as Demi Lovato warmed up the crowds with singles such as "La La Land" and "Get Back."
Lil WayneVia Young Money / Cash Money / Republic / VevoNicki MinajVia Young Money / Cash Money / Republic / Vevo
Nicki might be one of the biggest rappers in the world now, but she got her start by opening for mentor Lil Wayne.
RihannaVia Def Jam / VevoKanye WestVia Roc-A-Fella / Def Jam / Vevo
Rihanna opened for Kanye long before he announced his presidential campaign.
The Pussycat DollsVia Interscope / VevoLady GagaVia Interscope / Vevo
The Pussycat Dolls
Before anyone had memorized the number of "rah rah's" in "Bad Romance," Mother Monster was opening for Nicole Scherzy and Co. on their Doll Domination Tour in 2009.
Katy PerryVia Capitol / VevoNo DoubtVia Interscope / Vevo
Katy Perry helped No Doubt thrill crowds on their 2009 arena tour pre-"California Gurls."