June Lockhart has died. She was 100.

The actress died on Thursday, Oct. 23, at 9:20 p.m. local time in Santa Monica, Calif., PEOPLE can confirm.

Lockhart’s cause of death was natural causes. Her daughter, June Elizabeth, and her granddaughter, Christianna, were by her side when she died.

Funeral services for Lockhart will be private. In lieu of flowers, her family is instead asking for donations to be made to The Actors Fund, ProPublica and International Hearing Dog, Inc.

The actress’s career spanned film and television. Her films included A Christmas Carol, Meet Me in St. Louis and She-Wolf of London. On TV, she had starring roles on Lassie and Lost in Space. She was one of the last surviving stars from the Golden Age of Hollywood.

Lockhart was born in 1925 in New York City. Both her parents, Gene and Kathleen, were also actors.

She made her stage debut at just 8 years old in a Metropolitan Opera production of Peter Ibbetson. Her first film role came in 1938’s A Christmas Carol, where she played the daughter of Bob Cratchit, played by her father, with her mother as his wife.

“I thought my parents were wonderful as the Cratchits, and it was just great fun to see how a film was made,” Lockhart remembered to the Ames Tribune in 2014. “I loved the Victorian costumes.”

“We used to perform it every Christmas at home for our dinner guests,” she said. “So I had already appeared in it, with my parents, in our living room for many years prior to doing it for MGM.” She said her family particularly loved that her first-ever words in a movie were “I know, I know — sausages,” explaining, “It’s become a family joke, and we all shriek with laughter when we watch it now.”

Lockhart’s early film roles included All This, and Heaven Too, Adam Had Four Sons, Sergeant York and She-Wolf of London. In 1944, she appeared in another Christmas film — Meet Me in St. Louis.

Lockhart appeared on Broadway twice, in For Love or Money in 1947 and The Grand Prize in 1955. For the former, she won the Tony for outstanding performance by a newcomer. ”I like it all, but I think the hardest to do is theater,” she told the Chicago Tribune in 1987. “Television is fun. But theater is night after night after night.”

She began making TV appearances in 1949. She had guest appearances on shows including Hallmark Hall of Fame, Shirley Temple’s Storybook, Wagon Train and Gunsmoke. She worked in a lot of early Westerns, telling the Burlington County Times in 2015, “I loved the period costumes with the long gowns and their cinched-in waists. The stories were also marvelously written and could be quite provocative for their time.”

In 1958, she was cast on the TV series Lassie. She took over the role of Ruth Martin from Cloris Leachman. The series followed Timmy, played by Jon Provost, on his adventures with the iconic title dog.

Lockhart and Provost became very close. ”My own mother might forget my birthday, but June never does,” Provost told PEOPLE in 1994. Lockhart was an Emmy nominee for the series in 1953 and 1959.

After her time on the show ended, she was cast on Lost in Space from 1965 to 1968. The show was inspired by the novel The Swiss Family Robinson, and Lockhart played the mother of a family of space colonists. In 2021, she had a voice cameo in Netflix’s remake series, also titled Lost in Space.

People would tell her that watching Lost in Space inspired them to become scientists, she told NPR in 2004. “I did Lassie for six years, and I never had anybody come up to me and say, ‘It made me want to be a farmer,'” she joked.

When the series ended, she joined Petticoat Junction for its final two seasons, from 1968 to 1970. Other TV roles for her in the following years included spots on Marcus Welby, M.D., Magnum, P.I., Knots Landing, Murder, She Wrote, Full House, General Hospital, Grey’s Anatomy and Babylon 5. She also appeared on Roseanne as the mother of Martin Mull’s Leon, which she told PEOPLE was “the highlight of my career,” in 1995. In total, she had over 150 film and TV credits.

She often played mothers on TV, but she insisted she was a lot more interesting than her screen alter egos. “I love rock ‘n’ roll and going to concerts,” she told the Chicago Tribune in 1994. “I have driven army tanks and flown in hot-air balloons, and I go plane-gliding — the ones with no motors. I do lots of things that don’t go hand-in-hand with my image.” She told the outlet that she’d recently done a voiceover part for Ren and Stimpy because it was her favorite show. “I am such a fan, I try never to miss an episode,” she said.

The actress had two stars on the Hollywood Walk of Fame, one for movies and one for TV. They were dedicated on the same day in 1960. Lockhart was also a space enthusiast, and in 2014, NASA honored her with the Exceptional Public Achievement Medal. “I’ve been to two space shuttle launches and worked with NASA since the 1970s, addressing their employees and traveling on NASA’s behalf to promote the agency,” she told The Denver Gazette at the time. “So I’m absolutely thrilled by this recognition. No other actress has received this honor.”

She also loved following the American presidency, an obsession that began when she met President Harry Truman in 1948. She told the New York Post in 2016 that she asked him what it was like being in the Oval Office. “He looked at me, and said, ‘It’s just like being in jail.’” President Dwight Eisenhower’s press secretary Jim Hagerty gave her a lifetime press pass, and she attended press briefings in D.C. and California for the next 47 years. Her love of following the news also made her a frequent and successful contestant on celebrity trivia shows.

Lockhart married John F. Maloney in 1951. They shared two daughters, Anne and June Elizabeth. She divorced Maloney in 1959.