Everybody has to start somewhere. "The Ugly Truth," the bawdy, R-rated romantic comedy that opens this weekend, features two stars that only recently became bona fide A-listers. For Katherine Heigl, the journey was a two decade-long slog, starting as a child model and paying her dues on TV and in movies. Gerard Butler's acting success, on the other hand, was born from an epic failure in another line of work.

Here are the surprising stories of the two very different roads to fame that eventually brought Heigl and Butler together.

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Katherine Heigl
Heigl got her start in the biz at the tender age of nine when her aunt sent photos of her to a few New York modeling agencies. Heigl was almost immediately signed, and soon she was sporting the latest fashions in Sears and Lord & Taylor catalogs. Not long after that, she appeared in a TV spot for Cheerios. Hollywood came knocking.

Heigl made her film debut in the same movie that "Dollhouse" star Eliza Dushku first got her start: the 1992 romantic drama "That Night." As her burgeoning movie career started to take off, Heigl alternated between appearing in well-regarded indie films like Steven Soderbergh's "King of the Hill" and D-grade schlock like "Under Siege 2: Dark Territory" and "Bride of Chucky. " Throughout her teens, she balanced school work with her modeling and acting work, slotting shoots in during weekends and school vacation. She did, however, make time to date "Blossom" star Joey Lawrence.

Almost immediately after graduating from New Canaan High School in Connecticut, she and her mom -- who remains her manager to this day -- piled their stuff in the car and drove to L.A. In 1999, she landed a gig on the cult TV series "Roswell" as an alien-human hybrid. The show sputtered along for three seasons before finally succumbing to a terminal case of low ratings. For the next year or so, Heigl's career stalled. She was in contention for the leads in "Felicity" and "Alias" but failed to land both parts. She was thinking about quitting the industry altogether until she managed to nab the role of Dr. Isobel "Izzie" Stevens in "Grey's Anatomy."

In spite of her growing fame from the series, her film career remained hit or miss; she played opposite Tom Sizemore in the 2006 crime thriller "Zyzzyx Rd," which earned a paltry $30 (yes, you read that right), landing it in the record books for having the lowest U.S. box-office haul ever. That changed when Anne Hathaway bowed out of "Knocked Up" because she objected to a planned shot of her giving birth. Heigl beat out Kate Bosworth, Jennifer Love Hewitt, and Mila Kunis for the part. That film's enormous box-office success made Katherine a bankable movie star, and her first leading role in "Bride of Chucky" was also a surprise hit.

Some well-publicized contract disputes and personality clashes put into question whether or not Heigl would return for a sixth season of "Grey's Anatomy." And even though it looked like Izzy was at death's door on the season finale, she will return, and Heigl will continue to juggle her TV and movie work as she has for the past 17 years.

Gerard Butler
Gerard Butler didn't do any professional acting until he crashed and burned as a lawyer.

That's right, the future King Leonidas was not only a law student at Glasgow University, he was the president of the law society there. He seemed set to lead a quiet, if lucrative, life as a Scottish lawyer until he took a year off to travel. He made his way to Venice Beach, California, where he quickly shed any semblance of a buttoned-down student. As he told Esquire Magazine, "I was out of control." While there, he drank like a sailor, and as a result, repeatedly wound up getting hauled off to jail.

Though he eventually did return to Scotland to finish his degree, Butler's wild man side refused to go away. He was fired the following year as a trainee lawyer by the firm he was working for -- an almost unheard of occurrence. With his legal career officially toast, Butler went to London the next day to try his hand at acting.

Though his first gigs were in the London theater, he soon transitioned to the silver screen with small parts in "Tomorrow Never Dies" and "Mrs. Brown," opposite Judi Dench. Not long afterward, he landed his first leading role in the TV miniseries "Attila," playing as everyone's favorite plundering barbarian. From there, the roles started piling in, including as Lara Croft's ex-lover in "Tomb Raider: The Cradle of Life" and Christian Bale's best friend in "Reign of Fire." Then, in a surprise move, director Joel Schumacher cast Butler -- who had no formal vocal training -- over John Travolta and Antonio Banderas in the lead for "The Phantom of the Opera."

Yet it wasn't until Butler stripped down and bulked up in "300" that he was launched into the ranks of A-lister. He trained for four solid months to get into fighting shape, working out with a mountain climber, bodybuilder, and team of stuntmen to become the hulking king of the Spartans. He got so burned out on working out that after filming he didn't go back to the gym for eight months. But it opened doors for him, allowing him to stretch in the romantic drama "P.S. I Love You," the family adventure "Nim's Island," and the crime caper "RocknRolla." But don't think he's gone soft; he'll be shooting it up this September in the action flick "Gamer."

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