ALEC BALDWIN’s little girl is growing up – and she’s in BIG trouble with her hotheaded papa!

The 54-year-old actor – who’s been known to lose his cool once or twice – went ballistic recently when he found out his 16-year-old daughter Ireland had post­ed a half-naked picture of herself on the Internet.

In the shot, which was taken in front of a mirror and went out to her 20,000 Twitter followers, Ireland is wearing an itty-bitty bikini that leaves little to the imagination.

But the risque tweeting didn’t end there. While out for a sushi dinner with mom Kim Basinger, Ireland post­ed that “sea urchin sashimi is sushi sex explosion in your mouth.”

Needless to say, daddy Alec was NOT pleased!

“He read her the riot act,” said a source. “Alec told Ireland, ‘Look, you never know what kind of creeps are out there, leering at your picture!’”

Ireland reportedly told Alec to “chill out.” She also explained that she’d wear the same kind of bathing suit to the beach.

 According to the source, Alec fired back: “That’s fine when you’re at the beach… but not when you’re splash­ing it all over Internet!”

This isn’t the first time Alec has blown up over his daughter’s behavior.

In 2007, the “30 Rock” star made headlines by leav­ing an irate message on the then-11-year-old’s voice mail. In it, he called her a “rude, thoughtless little pig” for not answering his calls.

Alec later apologized for the tantrum – and Ireland now claims it didn’t really bother her. She dismissed the episode, saying her father talks like that when he’s “frustrated.”

But the source says Alec – who recently tied the knot – has little tolerance for Ireland’s bad-girl behavior, adding: “This latest argument has Alec watching over her like a hawk.”