Mary Louise Weller, the actress best remembered as Mandy Pepperidge — the straight-laced sorority girl who gets tangled up with John Belushi's Bluto in National Lampoon's Animal House — has died at 79, one day before what would have been her 80th birthday.

Weller died on October 1 following a brief illness, according to Deadline, which first reported her passing. Her longtime partner, Michael Roy Curtis, confirmed the death, and outlets including FOX 26 Houston noted the news was also carried by Variety, The Hollywood Reporter and Legacy.com. A specific cause of death has not been disclosed.

A Fixture of Late-'70s Hollywood

Before she became a cult-film face, Weller was a working New York model who broke into movies with an uncredited role in 1973's Serpico. But it was 1978's Animal House — the Belushi-led fraternity comedy that helped invent the modern gross-out genre — that made her a recognizable name to generations of fans, according to Extra. Her other film credits include The Evil, The Bell Jar and Larry Cohen's creature feature Q, and she racked up guest spots on a string of era-defining TV shows: Starsky & Hutch, Kojak, Fantasy Island, CHiPs and Quincy, M.E.

Off screen, Weller was known among friends as an accomplished equestrian, and she came by her show-business instincts honestly — her father counted entertainer Danny Kaye as a friend, and she once joked, per FandomWire's account of a 2012 interview, that she "flew out of the womb in full camera makeup and screaming, 'HAIR! MAKEUP!'"

Tributes from those who knew her personally began circulating quickly. Friend David Marks wrote on Facebook, as cited by FOX 26:

"Beautiful Mary, friend, actress, model, equestrian, passed away quietly."

Animal House remains one of the most influential comedies in American film history, credited with launching the modern college-comedy genre and cementing Belushi as a star before his own death just three years later. Weller's Mandy — caught between Bluto's chaos and her uptight boyfriend — was a key supporting piece of that ensemble, and she remained a beloved figure on the convention and nostalgia-film circuit in the decades since, fans say.

No memorial service details had been announced as of this writing. Weller is survived by Curtis, her longtime partner.