Looking back at the day he wrote "My Humps," Will.I.Am remembers one of the most musically challenging times of his career.

"It was real intricate, a lot of horns, like, 'No, no, no, instead of going to B flat, go to A minor,' " he recalled.

But all that fussing was for a different song, "Lovely People," for Earth, Wind and Fire's new album. He wrote "My Humps" during a five-minute break.

"You've got, like, a real idiotic approach to music, and then you've got the sophisticated all happening in the same six hours," he said, laughing.

Idiotic or not, "My Humps" is a smash that's suddenly redefined "humps" and "lovely little lumps" as part of the human anatomy.

Fittingly, the song stemmed from a conversation Will was having with a friend when a beautiful woman walked by. When the rapper asked, "Whatcha gonna do with all that junk," his friend replied, "You should turn that into a song." He got a second opinion when he crossed paths with the woman again and stopped her.

"I was like, 'Hey, my homeboy told me I'm supposed to make a song about you,' and she said, 'Oh yeah, well how's it supposed to go?' " Will recalled. "I was like, 'What you gonna do with all that junk, all that junk?' And she was like, 'That's probably the best pickup line I ever heard.' I was like, 'No, I'm not trying to pick you up!' "

The Peas are still insisting the song is more than just a pickup line -- that it's about a woman dissing a man.

"I would hate for my sister to be treated like that," Will explained. "Writing it, I wanted to make it to where a girl would feel like, 'Yeah, that's right. [Will starts dancing.] Shoot, don't pull on my hand!' "

"I go out to the clubs and I love to dance and shake my booty, and also at the same time it doesn't mean I'm going home with you," Fergie further explained.

Although "My Humps" is still climbing the charts, the Peas are prepping the release of Monkey Business' next single, "Pump It."

Will wrote that track after picking up a CD in Brazil because the cover featured a beautiful woman lying on a beach. When he put it in a few days later, on a bullet train in Japan, he realized it was surf-guitar legend Dick Dale's "Misirlou," most recently made famous by its use in "Pulp Fiction."

"I'm thinking it's gonna be samba and it's Dick Dale, but then it made sense that the girl was on a beach, they just got their cultures mixed up," Will said. "So then I flipped the [guitar riff] and everybody's partying on this bullet train and I got my little mic and ... I'm like, 'Louder! Pump it!' "

While making the track, Will started envisioning a "Crouching Tiger, Hidden Dragon"-like fight scene on the train, except the passengers are using breakdancing with their martial arts. He's since approached veteran video director Francis Lawrence (coming off his feature film debut, "Constantine") about turning the idea into a mini-movie.

In the meantime, the Peas have already finished another video, for "Like That," a rawer hip-hop track featuring Q-Tip, Talib Kweli, Cee-Lo and John Legend (see [article id="1505570"]"Black Eyed Peas Put Two In A Pod With Simultaneous Singles"[/article]).

"I don't know if anyone's gonna see it, with the politics and all, but thank God for iTunes video downloads and all that stuff, 'cause now there's a place for all that to get seen," Will said.