To determine which young stars are budding into moguls, we took a look at Hollywood's top earners at or under age 35 with revenue streams coming from more than one field. (For consistency we calculated pretax earnings from all entertainment-related ventures between June 2009 and June 2010.) To make the cut, these stars also had to have the potential to grow both their brands and fortunes in the years ahead.

Estimated Earnings: $87 million

One half of the most powerful couple on the music scene, Beyoncé continues to expand her business empire beyond her songstress roots. Endorsement deals with companies ranging from Nintendo to L'Oréal and her growing House of Deréon fashion line bring in millions of dollars per year. And that's on top of the $86 million she grossed from 90-plus dates on her world tour.

Estimated Earnings: $64 million

Not long ago much of the world had written off Britney Spears as a celebrity flameout. But over the last year Spears logged the fifth-highest-grossing tour in the world, bringing in $130 million in gross box office receipts over 98 dates. High-profile deals with Elizabeth Arden perfumes and Candies, which includes her own fashion line, suggests Spears will remain in the spotlight for reasons other than attacking photographers' cars with an umbrella or shaving her head.

Estimated Earnings: $62 million

A newcomer to the Celebrity 100 list of the world's most powerful stars last year, Lady Gaga broke down the door to fame with outlandish outfits and quirky videos. In addition to the kind of energy that propels a 106-date tour that grossed $95 million, Lady Gaga is also a marketer's dream, teaming up with Polaroid, Virgin Mobile, Monster Cable and Viva Glam. Billboard recently named her artist of the year for 2010.

Estimated Earnings: $48 million

The teen star behind Disney's lucrative Hannah Montana franchise has now matured into a serious entertainment draw, averaging a nightly gross box office of $1.2 million across 57 tour dates. A starring role in the movie The Last Song, heavy radio play for her hit "Party in the U.S.A." and her cut from all of those Disney shirts with her face on them add up to a large bump over her earnings from last year. Whether she can maintain that appeal without the Disney machine propelling her is the $48 million question.

Estimated Earnings: $45 million

Swift's 100 live dates during the 12-month period grossed $54 million. What's more, she's one of the few artists who can still convince millions of fans to legally buy music: 2.6 million copies of Speak Now were sold in the album's first eight weeks on shelves. Splashy endorsement deals with Sony and CoverGirl have helped the country star's bottom line, while high-profile romances have kept her name in the news.

Estimated Earnings: $44 million

Stateside audiences may know Pink mainly as the singer who sang swinging from a trapeze at award shows, but the outspoken pop star is a major hit overseas. Her 133-date 2009 world tour--the seventh-highest-grossing in the world--brought in more in box office receipts than Beyoncé, despite playing only a handful of dates in the U.S., and logged a run of sellouts of major arenas in Australia. She has lent her recognizable name to a host of charities and will reportedly grace the silver screen later this year as the voice of Gloria in Happy Feet 2.

Estimated Earnings: $35.5 million

Though they stepped into the limelight as part of a Disney show, the Jonas Brothers ache to be taken seriously as musicians. They launched a world tour that grossed $95 million, including $30 million overseas, while playing to an average audience of 14,000 fans a night. They pad their wallets still more with their collection of Disney shows, flicks and specials.

Estimated Earnings: $32 million

Until How Do You Know? hit theaters in late December, Witherspoon's face hadn't been seen on the big screen since Christmas 2008, when she starred with Vince Vaughn in Four Christmases. Meantime, both a tabloid-worthy love life and a lucrative endorsement deal with Avon have kept her in the headlines.

Estimated Earnings: $25 million

The 30-year-old beauty, married to NFL quarterback Tom Brady, remains the industry's most sought-out face and body. Aside from starring in campaigns that included True Religion jeans and Dolce & Gabbana, Bundchen has her own lucrative sandals line, Ipanema by Gisele.

Estimated Earnings: $25 million

Radcliffe will soon have a chance to prove he's more than Harry Potter. The top-grossing series is slated to come to an end later this year with the second installment of Harry Potter and the Deathly Hallows, though film royalties and revenue from Potter-related merchandise should continue to roll in. Meantime, the franchise star has been busy beefing up his theatrical chops on the stage.