Angela Margaret Cartwright is an English-born American actress primarily known for her roles in movies and television. On television, she played Linda Williams, the stepdaughter of Danny Williams in the long-running TV series The Danny Thomas Show, and Penny Robinson in the 1960s television series Lost in Space. Cartwright's most famous movie role was the part of Brigitta von Trapp in the film The Sound of Music (1965). Her older sister is actress Veronica Cartwright.

Danny Thomas was an American actor, singer, nightclub comedian, producer, and philanthropist. He created and starred in the Danny Thomas Show. In addition to guest roles on many of the comedy, talk, and musical variety programs of his time, his legacy includes a lifelong dedication to fundraising for charity. Most notably, he was the founder of St. Jude Children's Research Hospital in Memphis, Tennessee, a leading center in pediatric medicine with a focus on pediatric cancer. St. Jude now has affiliate hospitals in eight other American cities as of early 2020.