'Father Knows Best' Star Lauren Chapin Dead at 80

Lauren Chapin -- who played the youngest child, Kathy “Kitten” Anderson, on the beloved 1950s TV show "Father Knows Best" -- has died.

Her son, Matthew Chapin, announced the news on social media Tuesday evening, writing ... "After a long hard fought battle over the past 5 years, the time has come. My mother Lauren Chapin passed away from her battle with cancer tonight."

Lauren kicked off her acting career with an uncredited role in 1954's "A Star Is Born" starring Judy Garland, as well as the CBS series "Lux Video Theatre" before being cast as the precocious Kitten in 'FKB.'

"Father Knows Best" ran for 6 seasons, and after it ended, she appeared on an installment of "General Electric Theater" alongside Steve Allen and Jayne Meadows as well as the 1976 comedy musical "The Amorous Adventures of Don Quixote and Sancho Panza." She also returned for a 'FKB' reunion and Christmas special in 1977, and played Ace's mom in 1980's "Scout's Honor."

She took a decades-long acting hiatus before snagging a recurring role in the family drama "School Bus Diaries" in 2016.

Lauren had a difficult life, claiming her father sexually abused her as a child. She also dealt with substance abuse and legal woes, and was addicted to heroin until she was 25, according to the Orlando Sentinel. She was also married and divorced by the age of 19.

Reflecting on her past woes, she told the Sentinel in 2001 ... "The most important thing is not that we have a past. But it’s what we do with the present that counts."

In her adult life, she managed artists, including her daughter, Latin pop singer Summer Healy-Chapin. She also worked as a counter manager for Guerlain perfume in Florida in 2001 and was heavily involved in her church.

She wrote 2 books and helped raise more than $2 million for underprivileged and abused children as well.

Lauren was 80.