Jennifer Aniston is under fire for using a controversial word on live TV.

The star appeared on Live! with Regis and Kelly to promote her new movie The Switch, and she was asked about the Harper's Bazaar photo shoot of her posing as Barbra Streisand.  

"You play dress up!" observed Regis Philbin.

"I play dress up! I do it for a living, like a retard," said Aniston.

Aniston's remark drew a big laugh from the audience, but many advocacy groups for the mentally challenged say the "r-word" is not funny!

The crack is now being blasted as "extraordinarily offensive and inappropriate."

"Frankly, someone in her position ought to know better," said the CEO of one organization. And a representative for the Special Olympics also went after Aniston, writing, "The pervasive use of the r-word, even in an off-the-cuff, self-deprecating manner, dehumanizes people...and perpetuates painful stereotypes."

Aniston isn't the first high-profile personality to ignite controversy with the r-word.  White House Chief of Staff Rahm Emanuel sparked a firestorm earlier this year when it was revealed that he used the term "[expletive deleted] retarded" in a private political strategy session.

Emmanuel apologized, but Sarah Palin is still so angry she denounced him on her Facebook page, calling his r-word comment "crude and disrespectful."