Alexa Ray Joel collapsed onstage during her Saturday concert at Cafe Carlyle in NYC and was rushed to the emergency room, but she will be alright.
Billy Joel and ex-wife Christie Brinkley's only daughter, 28, was diagnosed with vasovagal syncope, one of the most common causes of fainting.
"She didn't feel well all day and got sick," a source close to the singer says.
"But she wanted the show to go on. She psyched herself up to do it and then got sick onstage. It's fine. She didn't want to cancel. She's 100 percent fine."
Alexa Ray says, "I was excited and determined to fulfill my final performance, and I really wanted to end my run with a bang, but this was not what I had in mind."
"And hope I have the opportunity to make it up to the wonderful audience very soon. Thanks for all the concern," said the talented singer-songwriter.
The songbird made other headlines earlier this month after alleged Alexa Ray Joel plastic surgery photos revealed just how grown up she's become.
While many people online speculated that Joel underwent extensive cosmetic procedures, she slammed the rumors personally on Us Weekly.
"I have only gotten one nose-job done. That is the absolute extent of the surgeries I have had," she posted on the celebrity gossip site (for real).
"I'm very sorry to disappoint everyone who wants to believe that I have had multiple surgeries, but that just simply isn't true," she wrote, adding:
"I don't have low self-esteem, contrary to all of your unsubstantiated opinions. I accept and love myself for exactly who I am, as every empowered woman should!"
Check out slide #7 for the before and after pics in question: