The actress, who is married to Keith Urban and is the former wife of Mission: Impossible actor Tom Cruise, told Harper's Bazaar that she struggled with nerves in the early days of her career.
Kidman admitted that she relied on Cruise for support during public events when she felt unnerved by the situation.
"In those early years, it was like, 'I'm here and I'm clutching onto your arm and it all feels a little overwhelming and really strange'.
"And I was shy. Deeply shy. I didn't feel comfortable at all. But I felt very comfortable at home.
"[I'm attracted to] a bigger, stronger personality; that's what I've been drawn to. I need protection. Everyone wants to feel someone's got their back."
The 45-year-old also revealed her current husband had helped build her self-esteem through their relationship.
She said: "He just gave me confidence through just being very kind to me and understanding me. Opening me up to trying things, my sexuality, those sorts of things."
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