The "Vampire Diaries" actress shared her happy engagement news on Instagram Wednesday, where she penned a caption seemingly inspired by the upcoming Halloween holiday.

Alongside a series of sweet photos from the proposal, Nina wrote ... "RIP boyfriend, hello fiancé 💍♾️."

In the images, the Olympian lifted the starlet off the ground surrounded by candles and white flowers. The pair matched for the romantic date night, as they both wore all-black ensembles for the special occasion.

Nina gave an up-close look at her new sparkler, too ... with one photo featuring her new, massive diamond ring -- that shines brighter than Shaun's many gold medals.

Shaun also shared a few pics from when he got down on one knee ... confirming in the caption that Nina did, in fact, say "YES" to his big question.

The duo spilled some of the proposal details to Vogue, with Shaun confirming he had been planning to pop the question for some time.

Per the professional snowboarder, he originally planned to ask Nina to marry him over the summer ... but her dirt bike accident and subsequent knee injury derailed that plan.

SW then considered moving the proposal to November, when he and Nina planned to be in Cape Town, South Africa for the Earthshot Prize Ceremony. However, he had to shift his plan again after Nina thought it might happen -- with her friends asking her if he was going to pop the question during the trip.

Shaun finally settled on a romantic NYC surprise and, despite the coordinated outfits, the actress appeared totally floored by her man's question. Nina wasn't feeling well days before his planned date, but he was committed to sticking to the plan so he made a fake invitation to a CFDA/Vogue dinner with Anna Wintour he knew Nina wouldn't want to miss.

Countless fans and celebrity friends have already congratulated the future bride and groom ... including Zoey Deutch, Julianne Hough, Katie Couric, among others.

Nina and Shaun first got together back in 2019 after meeting at a workshop organized by Tony Robbins ... though, they didn't become Instagram official until May 2020.

From there, the twosome has become practically inseparable ... traveling the globe together with their A-list friends and hitting a number of red carpets.