(CNN) -- This year has seen Johnny Depp morph into a chameleon, Anne Hathaway perform as a parrot, Jack Black play a panda and Katy Perry turn into a Smurf.
A-list celebrities are now scratching at casting directors' doors in their eagerness to voice animated creatures -- a move that would once have been considered professional suicide.
"There was a sense that actors who did animated work weren't at the top of their game career-wise," said Total Film editor Aubrey Day. "There was a stigma surrounding it."
Then Robin Williams let the genie out of the bottle in 1992's "Aladdin," magically transforming voice actors from faceless fill-ins to sought-after stars.
"When Robin came in -- whose career was flying at the time -- it showed people there was no stigma in animated work, and it opened the floodgates," said Day. "The success of that movie made film execs think, 'We've hit on something -- if we get celebrity actors in these roles, it will generate box office.'"
A roll call of big-name actors has followed -- from Tom Hanks as Woody in "Toy Story" and Eddie Murphy as "Shrek's" wisecracking Donkey, to George Clooney as the "Fantastic Mr Fox."
For studios, the draw is obvious: a bankable name on the poster that will entice parents -- the ones ultimately buying the tickets.
"If you can make parents think it's not going to be a painful two hours, that's a big advantage," said Day. "For adults, knowing there are A-list stars in a film adds a level of curiosity and an inclination to go and see it.
"They went to see 'Bee Movie' with Jerry Seinfeld because he was in it, and 'Antz' because they wanted to hear Woody Allen in an animation."
A celebrity is also infinitely more useful than an unknown voice actor in terms of PR, since they can be sent onto chat shows and red carpets.
For the A-listers themselves, animated films are now seen as credible projects -- even, since 2001, honored with their own category at the Academy Awards.
And with the success of the sector in recent years, animated films have become epic productions with budgets for A-list salaries. According to boxofficemojo.com, "Shrek 2" and "Toy Story 3" both grossed over $400 million.
Inevitably, there's still the sneaking suspicion that actors regard voice work as a cushy number. As Jack Black, who voices Po in "Kung Fu Panda 2," out later this year, quips: "Well obviously I don't have to do costume and make-up, and it's an easy piece of pie. Just role out of bed in your PJs and rock the mike for a few hours a month, and you've got a real cool movie."
That's galling for traditional voice actors, who regard theirs as a well-honed craft -- and who are increasingly consigned to bit parts.
Artists like the late Mel Blanc, the "Man of a Thousand Voices" -- who brought Bugs Bunny, Tweety Bird and Daffy Duck to life -- made successful careers out of their ability to voice multiple characters, often in the same film.
Their flexibility remains their trump card in the era of star casting, while celebrities ultimately need to sound enough like themselves to be recognized.
"That's the name of this game -- versatility," Nancy Cartwright, a veteran voice actor best known for being Bart Simpson, told CNN. "The more versatile you are, the better chances you have of getting hired. It's not enough to just have one voice."
In "The Simpsons," Cartwright not only voices Bart, but other characters including Nelson Muntz, Ralph Wiggum and Todd Flanders.
Far from being a cushy job, Cartwright says voice work is a performance -- and one that requires actors to find the physicality of the character, just as they would in a live-action film.
The way Cartwright holds herself changes when she is about to say a line as Bart, and she often gets so into character that she starts ad-libbing -- once snapping "eat my shorts" at a colleague and inadvertently creating a famous catchphrase.
Black got similarly carried away as his martial-artist bear, ad-libbing so often that co-star Angelina Jolie had to be brought back in to re-record scenes that had changed.
"I go headlong and really try and get into the fur of my panda character," Black told CNN. "I don't think about what it's like to live on a bamboo diet all of my life, but just the emotional reality of the scene ... I think you tend to overcompensate because you don't have the face and the eyes."
The production team helped Black and Jolie imagine what each scene would eventually look like.
"They are really great about showing us images, footage, something -- even if it's just a sculpture of your animal," said Black.
"They give as much as they can to give a sense (of it). But sometimes you really have to ask, because they give you five lines and you say your lines loads of times and they say, 'No, no, no, you don't understand -- while you are saying this you are dropping from the top of a 500ft building!'"
A-list stars, however, don't always guarantee success. A recent big-screen version of "Yogi Bear" failed to impress, despite help from Dan Aykroyd and Justin Timberlake.
"There is no direct correlation between the big name and the size of box office -- it's more: Is it a good marriage between the actor and the character they're voicing?" said Day. "That's the key about animation -- it's about correct casting, not stunt casting."