Wildlife presenter Kate Humble said she had a "panic attack" when discussing having children.
The 48-year-old BBC presenter said that there was still a stigma around childless women.
She has previously said that both she and her husband of 25 years Ludo Graham, 55 are not interested in having children, but the pair discussed what they would do if one of them had a change of heart.
She said she had “what I can only describe as a panic attack.
"I broke down in tears and said: ‘I cannot do it’. It was kind of a primeval response.
"I don’t know where it came from. It was so strong, and that was the moment that I thought: ‘I’m never going to change my mind’."
Ms Humble has spoken in the past about her decision not to become a mother, and said that there is still a “stigma” attached to women who make the same decision.
“By choice I have said I do not want to have children,” Kate said.
“And that still seems to be quite odd and you do still seem to be quite judged for it.”
She added that she was pleased to be able to support other women who feel stigmatised for not wanting children.
“It felt constructive, it felt like women at last could turn around and say: ‘at last there’s somebody there in the public eye who feels the same way we do’.
“Suddenly it’s becoming a topic of conversation.”
Kate has presented a number of popular wildlife programmes, including Springwatch, Autumnwatch, Animal Park and Lambing Live.
But she firmly rejected suggestions that her life’s devotion to animals is in any way a substitute for motherhood.
“Absolutely not. I don’t want a substitute. I never wanted kids.
"This is a completely different thing. I find animals just endlessly fascinating, in the way that people find children endlessly fascinating.
“For me, there is never a dull moment when you have an animal around.”