Danielle Spencer, the actress who played the lovably bratty and witty teenager on the 1970s hit sitcom “What’s Happening!!” and its spinoff, “What’s Happening Now!!,” before spending much of her adult life as a veterinarian, died on Monday at Chippenham Hospital in Richmond, Va. She was 60.

Danielle Spencer, who was a child actor on the '70s sitcom "What's Happening!!", died Monday of cancer, CBS 6 and The Hollywood Reporter reported Tuesday.

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.