Jocelyn Wildenstein's longtime partner, Lloyd Klein, spoke out about her death at age 84 in Paris on New Year's Eve.

Klein, a fashion designer, shared details about the events that led to Wildenstein's sudden passing and how deeply her death has affected him.

The engaged couple, who had been together since 2017, had plans to spend New Year together.

They had been napping for the holidays, Klein said.

"We had a nice happy hour that same night and were getting ready for the new year," Klein told People. "We took a little nap just to look good before getting dressed."

However, he awoke to find Wildenstein had died peacefully in her sleep.

"It's very sad. It's extremely sad," he continued.

According to reports, Klein attributed her death to pulmonary embolism. However, when asked by People about the cause of her death, he mentioned that he had phlebitis.

Phlebitis is an inflammation that causes blood clots, typically in the leg.

"Because of her phlebitis, the legs were very, very swollen, and the blood was blocked, and there was no oxygen in the brain," he explained.

Klein also said Wildenstein had been in positive spirits prior to their plans to ring in the New Year together despite her health problems.

"We were at the Ritz two days ago. We were having dinner. Everything was good," he recalled.

The pair spent the holiday in Paris together, where Wildenstein was seen out and about multiple times looking fit.

Wildenstein was a fixture in high society and was nicknamed "Catwoman" because of the number of extreme cosmetic procedures she had done over the years, which made her appear cat-like.

And just days prior to her death, Klein said she was "very happy" and "at the top of her game."

He said, "Two months ago, she attended the Chanel show. Everyone invited us to dinner. Everyone welcomed her with red carpet. Paparazzi were following us."

"It was the return to Paris," Klein added. "We were at the top of our game. Everything was at the top."