You might have spotted Fergie Duhamel (born Stacy Ann Ferguson) in purple spandex and red sequins in her early days on the 1983 Disney TV show, Kids Incorporated. Or perhaps in her 1991 girls band, Wild Orchid.

But it wasn't until she became a vocalist for the Black Eyed Peas in 2001 that Fergie's career really took off. As soon as the sultry pop star joined, the longtime hip-hop group -- built around rappers will.i.am, apl.de.ap and Taboo -- rocketed to superstardom, with massive hits like "Where Is The Love" and "Shut Up" from its 2003 album Elephunk.

And then came the Black Eyed Peas' fourth album, 2005's Monkey Business, which was an an even bigger success. It went four times Platinum in the U.S., and spawned four singles: "Don't Phunk with My Heart," "Don't Lie," "Pump It," and, of course, "My Humps." That song in particular became one of Black Eyed Peas' biggest hits ever, peaking at No. 3 on Billboard's Hot 100 chart and selling more than 2 million downloads alone.

As charts analyst Chris Molanphy tells us on Soundcheck, Fergie's role in the song -- and those repeated references to her "lovely lady lumps" -- helped lay the groundwork for her successful solo career.

In a conversation with Soundcheck host John Schaefer, Molanphy explains the puzzling success of "My Humps" and her massive follow-up hit "London Bridge (Oh Snap)," from her solo album The Dutchess, as part of the ongoing series That Was A Hit?!?

Chris Molanphy, on the novel success of "My Humps":

“My Humps” was the third single promoted from the second post-Fergie Black Eyed Peas album, Monkey Business. It already had a couple of hits like “Don’t Phunk With My Heart” and “Don’t Lie” but simultaneously, further down on the Hot 100 was another song. “My Humps” was unlike all the prior songs that featured Fergie in a supporting role, hype woman. This song is absolutely the staging ground for Fergie’s solo career.

But it doesn’t sound like the first song you reach for for a radio hit. It was climbing the charts on its own. It peaked at No. 3 and spent more time on the charts than any song from that album. What’s an important detail is that in 2005, Bilboard added digital sales to its Hot 100 chart. That meant the public could vote more directly. They probably gravitated towards this song for the comedy if anything.

We’re in 2014 folks, there are a lot of songs about booty on the radio. But if you think we’re body obsessed this year, you can thank “My Humps” for what we’ve seen in the past five to ten years.

On "London Bridge (Oh Snap)," and the defeat of Gnarls Barkley's song "Crazy": 

I can’t believe it got No. 1. Especially because it’s not particularly well-remembered. It’s a single entendre, it’s a “Hollaback Girl” for dummies. In case you’re all wondering -- it’s not an ode to a great cultural landmark, it’s a really thin metaphor for sex. It’s pretty bad.

I think the thing that offends me most as a chart fan, the pop charts are kind of my sports. I follow them the way I would a team and when I’m behind a song I root for that song. In the summer of 2006, it prevented easily the best song of that year -- some say of the 2000’s -- from going to No. 1: “Crazy” by Gnarls Barkley. “Crazy” had been parked at No. 2 stuck behind “Promiscuous” by Nelly Furtado. With just a few more points “Crazy” would go to No. 1.

Then in comes Fergie, and “London Bridge” went to No. 1 in three weeks, blocking “Crazy.” It’s doubly offensive. It’s a terrible song that blocked an unbelievably great song from being No. 1. That just drove me crazy.