Barbara Eden had a big secret while filming the first season of "I Dream of Jeannie."

Sixty years later, the actress is uncorking the truth of why the 1960s sitcom was first shot in black and white before switching to color.

"I was going to have a baby," Eden recently told People magazine. "And so they started fast. I think they thought I was going to die or something. They didn't want to invest the money in color."

‘I DREAM OF JEANNIE’ STAR BARBARA EDEN NEVER SAW HERSELF AS A SEX SYMBOL DESPITE ICONIC COSTUME

It had long been assumed that showrunners worried about how the show’s special effects would look in color, prompting them to play it safe, People reported. However, they were actually more concerned about hiding Eden’s growing baby bump.

"The same day that ‘I Dream of Jeannie’ sold, the doctor told me I was pregnant," Eden previously told the outlet. "I was thrilled. I was so happy, but I knew they'd have to replace me. Well, God love [‘I Dream of Jeannie’ creator] Sidney Sheldon. He got to work, and we did the first 13 shows with me pregnant."

Eden gave birth to her son, Matthew Ansara, on Aug. 29, 1965. The first color episode of "I Dream of Jeannie" aired Dec. 18, 1965, three months after the series premiered, People reported. Eden starred in the show from 1965 to 1970.

Ansara died in 2001 from an accidental heroin overdose. He was 35.

In 2021, Eden opened up to People magazine about losing her son. She and her first husband, Michael Ansara, had tried for nearly seven years to conceive before their son was born.

"When Matthew was clean and sober, he was such a beautiful human being, inside and out," said Eden at the time. "Drugs are inexplicable. It's so frustrating."

Ansara struggled with addiction for 14 years, cycling in and out of rehab.

"At first, we didn't recognize the behavior — the sleeping and the bouts of anger that would come up all of a sudden with this charming, darling boy," Eden admitted. "I was scared to death. I didn't know what to do. He was too young to know he needed rehab or help. It's a wonder that he lived to be 35."

Eden said she grappled with guilt after Ansara’s death.

"I don't think there's anything worse than to lose your child," she told the outlet. "As a parent, I had a lot of guilt and anger, and following his death, I was always on the edge of tears. Even though he was 35, he was still my baby."

"I began to speak with parents who were going through the same thing," she continued. "I think parents should know that it's not a bad thing to be strict with your child. If you know what's going on, you have a chance to help. Ultimately, it's up to them, but there's hope."

Eden said you can never truly "cope" with losing a child. Instead, she chose to live day by day and count her blessings.

"I'm really lucky," said Eden. "I have dear friends. I have a wonderful family, a very supportive husband. A dog who is adorable, but a brat! Yes, I'm very happy. I think life, everything, has to work itself out. There's a reason for most things, and I can't wish for it."

Over the years, Eden has kept busy performing. Most recently, on the 60th anniversary of "I Dream of Jeannie," Eden told Fox News Digital she never felt Jeannie’s powerful presence overshadowed her Hollywood career.

"I was always content and happy with her," she explained. "Even when I was doing ‘Jeannie,’ I was lucky enough to still be doing other things. I opened the MGM Grand in Las Vegas. I went back to singing again."

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"When we had breaks shooting ‘Jeannie,’ I would do another film in between and then go back. It was a long ping-pong. … And I’m so pleased that people still like her. I had no idea that the show would have the impact that it’s had all over the world."

"Back then, I didn’t think about being famous," she reflected. "I was just working. I didn’t have time to sit back and say, ‘I made it.’ I just didn’t. You can’t do that when you’re working hard."

"And I don’t think there was one secret behind the show’s success," said Eden. "I think it’s the combination of a really good idea, a terrific cast . . . it just worked. And that magic doesn’t always work. You can have very fine actors, but if the writing isn’t right, so many things can go wrong. But we were lucky."

The star hasn’t thought about what she would like to do next. She’s too busy staying active.

"I hope to accomplish whatever is thrown at me," she laughed. "I look forward to the next challenge."