Watch: Maura Higgins recalls sexual assault by taxi driver
The 31-year-old Irish TV presenter - who rose to fame after competing on the ITV2 dating show in 2019 - said she "sobered up" after waking to find his hand up his skirt.
Higgins was asked during a live Q&A on her Instagram stories about her worst encounter with a man.
She said: "So would you believe I actually have many. Like, a few. The worst one I've never ever opened up to any of you about and I don't even think I'm ready yet. It was probably one of the scariest things that's ever happened to me.
"I also had an incident with a taxi driver before, a long time ago, in Ireland. Silly me, I fell asleep. I probably told you this story, I don't know if I have.
"I fell asleep, my friends were dropped off before me and I was being dropped off alone.
"Because I lived on my own at the time and I woke up and his hand was right up my skirt, and honestly, I sobered up so quickly.
"I memorised his taxi number so quick and I still remembered it the next day."
Higgins did not go into further details or confirm if she reported the incident.
Higgins finished in fourth place on series five of Love Island, coupled with Curtis Pritchard.
She competed in Dancing On Ice in 2020 and presents the Irish version of make-up artist contest Glow Up.
She also appears as a contributor on This Morning and recently competed on Cooking With The Stars.
Earlier this year she revealed she is trolled for being "too skinny".
Higgins told The Sun: "I get it all the time. I get it so much. People writing ‘go and get a boob job’ or ‘you’re too skinny'.
"I’ve always spoken to my mammy about it and asked: ‘Why is it OK for people to turn around to your face and say: ‘God, you’re too skinny’? Would you ever say to somebody: ‘God, you’re too fat’? No, you wouldn’t."