Danielle Spencer, the actress best known for playing the quick-witted little sister Dee Thomas on the 1970s sitcom “What’s Happening!!” died on Monday at a hospital in Richmond, Va., her brother announced on Instagram. She had previously been diagnosed with breast cancer and undergone a double mastectomy and emergency surgeries. She was 60.

Spencer starred on the show from 1976 to 1979 and later reprised her role as Thomas in the spin-off “What’s Happening Now!!” She largely left Hollywood after that to become a veterinarian. Spencer wound up portraying a veterinarian in the 1997 film “As Good As It Gets.” Spencer was 60 years old.

Danielle Spencer, who played the precocious youngster Dee Thomas on the 1970s ABC sitcom What’s Happening!!, has died. She was 60. Spencer died Monday in a hospital in Richmond, Virginia, her What’s Happening!! co-star Haywood Nelson told The Hollywood Reporter .