Celebrity endorsements are a dime a dozen. Throw enough money at most movie or sports personalities and they're willing to put their name behind a product. But more and more stars of film, music and sports are more interested in starting their own businesses.

While the number of failed ventures by entertainers is considerable, several celebs have managed to defy the odds and become not just successful entrepreneurs—but titans of their industries, with companies that have multimillion- or multibillion-dollar valuations.

Certainly, their fame helps. But without a sound business plan and a quality product, no company can succeed. Here are some of the celebrities that have managed to carve out second careers for themselves in the start-up world.

—By Chris Morris, special to CNBC.com
Posted 18 April 2015

An allergic reaction to a laundry detergent spurred the actress to create a company that offered truly nontoxic options, but it took a while to get people to take her seriously. "It took three years of people not getting it," Alba said at the recent SXSW conference. "It was too big of an idea." She finally convinced Brian Lee of LegalZoom to work with her, and the company launched in 2011. It tripled its revenues to $150 million in 2014 and is now valued at nearly $1 billion.

The road Dre (real name: Andre Romelle Young) took to entrepreneurial success is pretty well known at this point. In 2006 the rapper partnered with Interscope Geffen A&M Records chairman Jimmy Iovine to create a headphone company in response to their joint disappointment with Apple's earbuds. The brand became a cultural phenomenon and last May was purchased by Apple for $3.2 billion.

Newman was a different sort of entrepreneur than most other entertainers. Rather than adding to his wealth, he gave 100 percent of the after-tax profits from his successful food company to charity. Initially offering just a salad dressing, the company grew to sell everything from popcorn to frozen pizza. Since its 1982 founding, Newman's Own has given more than $430 million to a wide variety of charities.

It makes sense that the woman whose 1990s haircut became synonymous with the decade would find success in the hair-care industry. Aniston is co-owner of Living Proof, a hair-care company founded by biotech scientists at MIT in Cambridge, Massachusetts. The goal, she said, is to simplify hair care. The company's products are now sold in more than 1,000 locations.

The basketball legend has become a business legend as well. Since leaving the NBA, he has assembled a significant portfolio of franchises, including AMC/Magic Johnson Movie Theatres, Burger King and 24 Hour Fitness. His Magic Johnson Enterprises also owns the Aspire television network, and he's part owner of the Los Angeles Dodgers. Today MJE is worth a reported $1 billion.

Simpson's music career didn't hit the heights of some of her peers, but her fashion sense proved especially lucrative. The one-time "Newlyweds" star recently sold part ownership in her Jessica Simpson Collection to Sequential Brands for an undisclosed amount. That purchase sent Sequential's stock up more than 12 percent; not a big surprise, seeing as the annual retail sales for the brand came in at approximately $1 billion.

Curtis Jackson's headphone venture is his best-known business outlet today, but the rapper has a long history as an entrepreneur. He hit a home run on his first investment, buying a stake in beverage company Glacéau, which was bought by The Coca-Cola Company for $4.1 billion, earning Jackson $100 million after taxes. He has also run two film production companies, is the founder of an energy drink company and runs a boxing promotion.

The golf legend who won 90 international tournaments now runs a multinational corporation that does everything from golf course design to real estate development to premium steaks. It even recently launched a small-business equity fund. Many people know him best off the links for his Greg Normal Estates wine, though. The company reportedly posted $300 million in revenues last year.

The Red Rocker started his entrepreneurial career as a landlord after making money in a band. When he was fronting Van Halen, he opened his first Cabo Wabo restaurant. Inspired by Jimmy Buffett's lifestyle brand, he expanded the operation, expanding into new markets and launching a line of tequila (which he ultimately sold for $91 million in two parts in 2007 and 2010). Today he's making rum—called Sammy's Beach Bar Rum—and running a restaurant chain of a similar name.

After appearing on three Sports Illustrated swimsuit covers, Ireland leveraged her name to create a multibillion-dollar business, offering everything from clothing to area rugs. The $2 billion in sales from the licensing business are more than double the estimated annual sales of Martha Stewart Living Omnimedia.

Starting with a record label in 1994, Combs showed a knack for picking stars, including Notorious B.I.G and Lil' Kim. He expanded his interests in the music field initially, then began to explore other outlets—the most famous of which is his Sean John clothing line. Combs also owns restaurants in New York City and Atlanta, a fragrance line and the DeLeón tequila brand. Two years ago he partnered with Comcast to launch Revolt TV, a music cable network.

The one-time talk show host's entrepreneurial accomplishments are well known by fans. With a reported net worth of $2.9 billion, she has launched her own cable network (OWN), owns and produces several hit TV shows, including "Dr. Phil" and "The Rachael Ray Show," and is co-founder of Oxygen Media, which is currently available in more than 77 million homes.

Having led the band No Doubt to international acclaim and establishing herself as a top-tier solo artist, Stefani took her iconic look and created a number of fashion companies. The largest is L.A.M.B., which stands for Love. Angel. Music. Baby. It has estimated annual revenues in excess of $100 million. She also launched the Harajuku Mini collection for children at Target stores in 2011 and recently partnered with denim guru Michael Glasser for a new line that goes on sale this spring.

Would Jake La Motta be a sushi sort of guy? It's debatable, but Robert DeNiro sure loves the stuff. The Nobu restaurant chain, which he co-founded, is an international sensation with more than 30 locations from New York to Tokyo to Moscow. He also owns several Italian restaurants, including Locanda Verde in New York, and last year co-created a new vodka brand, VDKA 6100.

The Academy Award-winning director knows good wine. Using proceeds from the first Godfather film in 1975, he purchased part of the storied Inglenook Winery (buying the rest 20 years later). In addition to the Napa facility, he also owns the Francis Ford Coppola Winery in Geyserville, California, near Sonoma.