The singer and actress took to Instagram on Tuesday -- hours after news first broke of DuBois death at the age of 74 -- to share a heartfelt tribute to her former Good Times co-star and personal friend.
"I am so very saddened to hear my longtime friend Ja’Net DuBois has passed away," Jackson wrote, alongside a slideshow filled with a trio of smiling snapshots of the pair taken over the past several decades.
"I saw first hand how she broke stereotypes and changed the landscape for Black women in entertainment. I’m grateful in recent years I had a chance to see her and create more lasting memories," she added. "I pray for comfort for all her family and friends. Thank you Ja’Net, I’ll miss you."
DuBois was best known for playing Willona Woods in the 1970s Norman Lear sitcom Good Times throughout the show's six-season run.
Jackson, then 11, joined the cast during the show's fifth season as Penny -- a young girl whom Willona adopts after she's abandoned by her abusive mother.
DuBois was found dead in her home in Glendale, California, on Tuesday, according to multiple reports. DuBois was reportedly in good health and had not been dealing with any known medical ailments when she died unexpectedly, in her sleep.
Apart from her role on Good Times, she was also known for co-writing and performing the iconic theme song "Movin' on Up" for another beloved 1970s sitcom developed by Lear, The Jeffersons.
Dubois -- along with a few of her former Good Times co-stars, including Bern Nadette Stanis, Jimmie Walker and John Amos -- made surprise guest appearances during the recent TV special Live in Front of a Studio Audienceback in December.