Janet Jackson has rejected a long-standing rumour that she had a baby in the 1980s.

For many years, people have speculated that the Together Again hitmaker secretly welcomed a child with singer James DeBarge in the early '80s.

However, Janet shoots down the gossip in her new self-titled two-part documentary, which begins airing in the U.S. on Friday.

"I could never keep a child away from James. How could I keep a child from their father? I could never do that. That's not right," she says during one interview, according to Page Six.

Janet went on to note that the rumour began to circulate while she was on the set of the TV series Fame in 1984.

"A lot of the kids thought I was pregnant 'cause I had gained weight and I had started taking birth control pills," she continues. "And back then, you could pick up weight taking them, and that's what happened to me, so that rumor started going around." And Debbie Allen, who also appeared on the show, backed up Janet's story.

"Where was the baby? Nobody saw a baby. I mean, she was there with us all day, every day. Where was the baby?" she asks. Janet and James eloped in 1984, with their marriage annulled the following year. The superstar and her ex-husband, businessman Wissam Al Mana, are parents to five-year-old son Eissa.