The Hot 'n' Sweaties
When the Yvette, the singer for The Groovy Girls Group decides to go solo for the talent show, the rest of the band takes a cue from this group that lip-syncs in order to better do their hot 'n' sweaty dance moves.
From the book, Rock and Roll Divas Supreme, (2005) number four in the Groovy Girls Sleepover Club series of "books." Based on the multi-culti dolls of the same name.
From page 35:
"Wait a minute!" Oki finally said. "What about that group the 'Hot 'n' Sweaties'?"
"What about them?" Reese asked.
"Well, during their concerts they do a lot of hopping and bopping around the stage, right?"
"Which is why they get hot 'n' sweaty!" Gwen replied.
"I heard that sometimes they lip-sync their songs-- you know, mouthing the words to the music during a concert-- so they can do the dance moves without sounding all breathless," Oki added.