Lady Gaga is far from the only pop star to find success with a fragrance. From October 2011 to September 2012, celebrity brands accounted for $140 million of the $2.9 billion in U.S. prestige fragrance sales -- up 32% year over year, according to market research company NPD Group. Leading the category the past year are Taylor Swift and Justin Bieber, whose Wonderstruck and Someday fragrances were, respectively, among the top overall prestige fragrance brands during the time period. (Someday was No. 18 and Wonderstruck No. 25 in dollars sold.)

"It's a celebrity party," NPD Group VP/ senior global industry analyst Karen Grant says. "The recent influx of new products is fueling prestige celebrity sales. Both Someday and Wonderstruck were launched in the second half of 2011 so they have had a wonderful ride in 2012 without any major [competitors]," she adds.

Why all the stink over perfumes? For one thing, they can be highly valuable to an artist's earnings portfolio. Jennifer Lopez, for example, has created more than 18 fragrances for Coty Beauty since her first, Glow, debuted in 2002. Lopez earns a significant portion of the more than $2 billion in sales the products have logged during the past decade.

Celine Dion's own line of Coty fragrances continues to thrive, as does Beyonce's. And Britney Spears' hugely successful line of fragrances for Elizabeth Arden have become a global powerhouse. "Britney Spears was the first recording artist we ever signed, and she remains to this day our leading celebrity fragrance franchise in terms of size," says Ron Rolleston, executive VP of business and creative development at Elizabeth Arden.

That explains why pop star fragrances are being snapped up by major buyers at a seemingly record pace. Bieber's fragrance line was acquired by Elizabeth Arden this summer; Rihanna's Rebelle, Reb'l Fleur and the upcoming Nude were recently purchased by fragrance retailer Perfumania; and Coty recently picked up Katy Perry's Meow, according to an executive familiar with the deal.

Now that fragrance companies are being pitched left and right by music managers to come up with the next celebrity scent, a few exceptions apply. For one thing, groups don't tend to work for a fragrance as much as solo artists. (Sorry, One Direction.) "It's problematic," Coty Beauty senior VP of global marketing Steve Mormoris says. "It's hard to create a message of intimacy and sexuality that's usually connected to one person."

Also, male-targeted scents have been tougher to crack than those aimed at females -- though Usher's UR cologne for Elizabeth Arden and Tim McGraw's Soul 2 Soul collection with wife Faith Hill for Coty have been strong sellers. "Men by their nature seem to be more committed to designers, whether it's Giorgio Armani or D&G or Calvin Klein or our guy John Varvatos," Rolleston says. Plus, their buying habits are just different, Mormoris adds. "They buy less and change fragrances less often," he says. "Females buy for themselves and buy frequently."