Beyonce grew to music superstardom as a "Destiny's Child" darling famous for singing about paying bills and, then, as a solo artist, singing about putting a ring on it.

Now, the 31-year-old singer has shocked fans and fellow singers alike with the debut of her first track in nearly two years, a gritty single titled "Bow Down/I Been On."

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In the song, released Sunday on her official Tumblr account, the Grammy winner, who has said she transforms into a character she calls "Sasha Fierce" on stage, uses two words unheard of in her music before, including the B-word.

"I know when you were little girls/You dreamt of being in my world/ Don't forget it/ Respect that/ Bow down b--es/ Don't get it twisted this is my sh-t," she sings.

"This is not a 'Good Housekeeping' moment for Beyonce," author Danyel Smith told ABC News. "This is a pop star moment for Beyonce."

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Beyonce's moment (this will be her fifth album) has drawn criticism from at least one of her fellow R&B singers, Keyshia Cole, who took to Twitter to call out Beyonce.

"First "Women need to Stick together" now b--es better Bow. Smh. But it's all G! Chicks stay shooting the sh-t. But when I speak my mind its a prob. #Well #StayMad," Cole tweeted Monday.

It's also surprising to fans and others who're not used to such lyrics from their pop star.

"The new song by # Beyonce is very disappointing especially since she now has a daughter. I've never been a fan & definitely wont after this," tweeted @SweetAngel CC.

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"I think hearing her use that word in a song is less expected than say if Rihanna or Katy Perry or Lady Gaga used it," Leah Greenblatt of Entertainment Weekly magazine said.