Stranger Things actress Millie Bobby Brown recounted on Thursday night's airing of The Tonight Show Starring Jimmy Fallon how her new engagement ring slipped off during Jake Bongiovi's underwater proposal and how her new fiancé's quick reaction saved it from plummeting to the ocean floor.

Although the couple announced their engagement on Instagram in April 2023, the bizarre proposal story was never publicly revealed. Brown decided to detail the underwater drama on Fallon's show because it was, "Too good of a story to not tell."

The 20-year-old actress explained that the couple had bonded over diving.

"We love diving," she said. "We got our diving licenses together."

During a vacation in April of 2023, Bongiovi reminded Brown that she had to be up early the next morning to dive at a spot they usually go to.

Brown said, "It’s boring. Let’s go somewhere new."

But Bongiovi insisted, "No, we have to go to this spot.”

At the dive site the next morning, the couple was many meters below the surface when the 21-year-old aspiring actor and model, handed his girlfriend a shell with a ring attached to it.

Brown laughed as she tried to imitate the unintelligible bubble speech produced by his breathing apparatus.

“And I looked at him and he was like, ‘Blub blub blub’.”

Brown tried to say "Yes" to his proposal, but the thumbs-up sign means "let's head to the surface" so that wasn't going to work. She finally settled for the "OK" sign made with the thumb and forefinger.

“So [the first sign], technically, would mean, ‘No, I don’t want to marry you. I want to go up.’ So I was like, 'Okay,'” she said. “I think it was underwhelming, but we freaked out.”

Bongiovi placed the ring on his fiancée's finger, but as she turned her hand with her fingers pointing down to show off the new ring, it slipped off.

"The ring falls off my finger and plummets so fast," she said. "It was like a cinematic movie. Jake threw himself [at the ring] so deep that the diving instruction said, ‘You can’t do that! Your ears! Literally, your brain will explode!'"

Brown continued, "He does a cinematic grab, opens his hand. He had saved the ring.”

The actress feels that Bongiovi's heroism in that moment is a reflection of who he is.

"And I feel that we will always have each other's back," she said. "And if anyone drops the ball, we got it."

When the couple got to the surface, Bongiovi revealed that the ring used for the underwater proposal was not her actual engagement ring. It was a prop.

Safely on the boat, Bongiovi asked Brown to marry him for a second time, but this time with a family heirloom (her mom's engagement ring).

Recounted Brown, “He was like, ‘You know, I bought you this ring (the prop) because your mum wouldn’t let me take her ring. My mom was like, ‘Absolutely not, Jake. You’re not taking my ring down there. I know you’ll drop it.’ And sure enough, I did.”

Bongiovi's parents, rock legend Jon Bon Jovi and mom Dorothea were on the boat to witness the second proposal.

Said Brown, "We were like, ‘We’re engaged, but also we have to tell you this crazy story that just happened.’”

Please check the video of Brown's fun retelling of the proposal story on The Tonight Show Starring Jimmy Fallon. The story starts at the 3:27 mark and runs for about three minutes.

Credits: Screen captures via YouTube.com / The Tonight Show Starring Jimmy Fallon.