Billy Joel and Christie Brinkley's daughter Alexa Ray is engaged

See the sweet announcement.

"He said to me: 'Before I met you, my world was in black and white. You colored it in between the lines,'" she captioned the first -- a pic of the two kissing. "It was the most beautiful thing anybody’s ever said to me. How could I possibly say no to that?!?!"

"...So I was completely taken off-guard, dumbstruck, and shell-shocked -- and FOR ONCE in my life, I had absolutely no words, and I couldn’t speak... I just kept staring at this ridiculously exquisite ring- and he was just hysterically laughing at me!!!" she continued in a caption to a photo of the two on a beach.

Gleason also chimed in, posting a picture of the couple's hands, proudly showing off the engagement ring captioned "Luckiest guy in the world!!!!"

The announcement came three days after Alexa's 32nd birthday on Friday.

The couple has been dating for five years.