Melissa Joan Hart was "warned" not to call in sick on Sabrina The Teenage Witch.

The 50-year-old star has reflected on her time as Sabrina Spellman on the classic Nickelodeon sitcom, which aired from 1996 to 2003, and admitted "some people" in the industry had advised her that skipping a day due to illness could damage her career.

She said in an Instagram video: "All right, let's talk about how many times I was sick on Sabrina.

"Two or three times that I had the full-on stomach bug, couldn't stop vomiting.

"But I was warned by some people, when actresses get sick, if you call out sick, that insurance might not insure you again for another project, and it could cost you your career."

In a recent interview, Melissa recalled "vomiting [her] brains out" and almost collapsing on set while filming season three finale The Good, the Bad and the Luau.

In the episode, Sabrina went to Hawaii for a family reunion, discovered that every Spellman has an evil twin and faced hers, Katrina, to determine which sister was which.

She told Entertainment Weekly: "I do remember with this episode in particular on that volcano, I was vomiting my brains out, and I asked our key grip to stand behind me in case I passed out and fell off because we were out in the sun."

Melissa added that she was battling illness while "trying to play" both twins.

She said: "I'm puking off camera. I'm standing there trying to play two of me. So when I see that I'm like, 'Oh, God, are you OK?'

"I think of little me like, 'Are you all right?'"

Despite the illness that overshadowed filming, Melissa still looks back on the episode fondly.

She said: "I always ask kids at any Comic Con, I say, 'Do you know the Spellman family secret?'

"I test people by how well they know the show if they know the Spellman family secret."

The entertainer shot to fame aged 15, playing Clarissa Darling in the Nickelodeon 1990s teen sitcom Clarissa Explains It All.

Although she did not like how growing up on TV sets held her back socially, Melissa appreciates how being a child star prepared her for adult life from an early age.

In February, she explained to PEOPLE: "I think it gave me a good work ethic. I think it helped me kind of grow up quickly, learn some things about myself in the world, take care of myself and but also, in that way, it kind of stunted my growth in other ways, socially."

Melissa has zero regrets because her parents, producer Paula Hart, 70, and 74-year-old actor William Hart, ensured that she did not miss out on childhood and was brought up with a sense of normalcy.

The star said: "I think my family did a really good job … I was in Girl Scouts, and we would go on family ski trips and things like that. So there was a lot of normal mixed up with this weird, crazy world."