Liv Tyler has revealed she has a signature "call" she can make in crowded places to help find her family.
The 'Gunpowder' star - whose father is Aerosmith rocker Steve Tyler - makes bird-like noises to communicate with her friends and family.
Liv explained to The Times newspaper: "It's a super New York thing. Kids who grow up in certain neighbourhoods have a call so they can communicate with their gang. We learnt it off friends who grew up in the projects. If you're a few blocks away and you hear the call then you immediately turn round."
She added her father has one too, revealing: "His is really funny. It's good to have your family call. It's the only way to get anybody's attention."
Liv, 40, grew up in New York's East Village with her mother, Playboy model Bebe Buell and singer/songwriter Todd Rundgren who for the first few years of her life she believed to be her father.
The 'Lord of the Rings' actress recalled the moment she spotted Steve Tyler's daughter Mia, from his marriage to the actress Cyrinda Foxe, and a Guns N' Roses concert, and realised she was her sister.
Liv said: "I saw this girl, Mia standing there and she literally looked like my twin. I turned to my mom and she looked at me with those big, beautiful doe eyes of hers. They were all glassy and she just started to cry. So I said, 'Is that my sister?' and Mom just said, 'Yes.' "
The mother-of-three also revealed when she first met her father she felt an instant connection with the Aerosmith frontman.
She recalled: "It was at one of Todd's shows. I felt a connection to my father that I'd never really felt with anyone before. I sort of fell in love with him, except of course it wasn't that, it was a kinship and a closeness."