Given Hollywood's obsession with youth, it's no wonder so many celebrities are barely old enough to drive. But while we may seem to be in an era of insta-fame, there are plenty of A-listers who toiled away for years and didn't get their star-making turns until they were -- gasp! -- over 40.

Regis Philbin

While Rege had served as host or co-host on a variety of programs in the decades prior, it wasn't until 'Live With Regis and Kathie Lee' was syndicated in 1988 -- when he was 57 years old -- that he became a familiar part of the TV landscape. (In fact, he's worked so much that he holds the Guinness World Record for "most time spent in front of a television camera.")

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Lucille Ball

One of Hollywood's most iconic actresses didn't become a household name until 'I Love Lucy' premiered in 1951 -- two months after Ball's 40th birthday. (Fun fact: Vivian Vance, who played landlady Ethel Mertz on the show, was only 42, but since Ball had envisioned the character to be more matronly, Vance was dressed in dowdier clothes to make her seem older and less attractive.)

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Susan Boyle

The Scottish singer became a literal overnight sensation at the age of 48 when her 2009 audition for 'Britain’s Got Talent' went viral. Her first album, released later that year, went to No. 1 on charts around the world, and she's earned two Grammy nominations from albums that followed.

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Viola Davis

In 2011, the stunning actress was an accomplished 45-year-old thespian with Tony Awards and an Oscar nomination under her belt -- but it was her phenomenal work in 'The Help' that year that put her name on everyone's lips and won her a spot on Time magazine's 2012 list of the 100 Most Influential People in the World.

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Dame Judi Dench

A well-known stage actress in her native Britain, Dench didn't become a global movie star until she was 61 and bossed around James Bond as M in 1995's 'GoldenEye.' Since then she's been nominated for six Academy Awards, winning one for playing Queen Elizabeth I in 'Shakespeare in Love.'

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Steve Carell

Longtime fans of Comedy Central's 'The Daily Show with Jon Stewart' (where Carell was a correspondent for six years) already knew how talented he was when, at 43, he struck box office gold playing someone only slightly younger in 2005's 'The 40-Year-Old Virgin.' And that same year, he began his long run on the American version of the TV show 'The Office.'

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Simon Cowell

We don't mean to be rude, but ... the cantankerous talent show judge had plenty of time to become jaded and cynical before entering the U.S. public consciousness, because he was 42 when 'American Idol' premiered in 2002.

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Leslie Nielsen

The late actor is best known for his hilarious turn in 'Airplane' (and later in the 'Naked Gun' franchise), but that didn't happen until 1980 when he was 54. Before that, he was actually a dramatic actor who'd appeared in hundreds of TV shows and B-movies. And no one ever called him Shirley.

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Alan Rickman

One of the finest movie villains ever didn't even get his first professional acting gig until he was in his 30s, and he was 42 before he broke out as Hans Gruber in 1988's 'Die Hard.' Then, over a decade later, he became famous to a whole new generation when he played Professor Snape in the 'Harry Potter' series.

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Dame Helen Mirren

She's done so much stage, TV and movie work that it's hard to point to just one role that made a star of the unabashedly sexy and candid Mirren, but what we do know is that she didn't start racking up award nominations until at least 1991 -- when she was 46 years old.

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