Tila Tequila’s Fiancé Drops Dead

Casey Johnson, heir to the Johnson & Johnson fortune and daughter of New York Jets owner Woody Johnson, was discovered dead early Monday in Los Angeles, the LAPD confirmed.

Her cause of death has yet to be determined.

SLIDESHOW: Casey Johnson’s short life in the fast lane.

Johnson was engaged to reality star Tila Tequila, who announced last month on a web video that her girlfriend had asked her to get married.

Tequila confirmed the news Johnson’s death on her Twitter account Monday afternoon.

“Everyone please pray 4 my Wifey Casey Johnson. She has passed away. Thank u for all ur love and support but I will be offline to be w family,†her Twitter feed read.

FOX411 EXCLUSIVE: Heiress “not taking care of herself,” Tila out of touch with fiancee for days.

Fox411.com’s Pop Tarts column spotted Tequila and Johnson posing for photos together at the Famous Stars & Straps party in Hollywood just a few weeks ago. According to an eyewitness, Tequila was holding up the starlet all night as she could “hardly stand straight.â€

Johnson reportedly struggled with substance abuse, and last month was arrested for theft after allegedly taking several items from the home of model Jasmine Lennard.

SLIDESHOW: Johnson’s bisexual fiancee Tila Tequila.

“Since the day I met Casey, I have only been a good force in her life. She’s been like a little sister to me,” Lennard told The New York Post. “I tried to get her off drugs and alcohol. I tried to get her into a 12-step program. I tried to help take care of her daughter. I’ve given her money.â€

Johnson has a young adopted daughter who was most recently reported in the care of Johnson’s mother, Sale Johnson.

The heiress had been cut off from much of the family fortune due to her substances abuse and erratic behavior, and was renting the home where she was found dead.

Johnson was a high school classmate of Paris Hilton, and told Vanity Fair in a 2006 interview that her decision to turn down Hilton’s invitation to be her co-star on “The Simple Life” was “the stupidest mistake of my life.”

Hilton eventually chose Nicole Richie. “I kick myself in the butt everyday,” Johnson told the magazine.

On hearing of Johnson’s death, Hilton told Life & Style magazine, “I’ve known Casey since I was a baby. She had a big heart and she was a good friend. I feel so sad, I don’t want to believe it.”

- With reporting from FoxNews.com’s Hollie McKay.