American singer Madonna has revealed her parenting struggles during an interview on US breakfast show Good Morning America. The 54-year-old Material Girl singer, who has four children - Lourdes Leon, Rocco Ritchie, David Banda and Mercy James - revealed she is a "pretty strict" parent.

Lourdes is Madonna's daughter with former lover Carlos Leon, while British director Guy Ritchie is Rocco's father. David and Mercy are the singer's adopted children from Malawi in Africa.

"Ever since my daughter got an iPhone she stopped talking to me," she joked, "Seeing my daughter at 16 - it's kind of uncomfortable. She's still my little girl and she's also a woman."

A 12-year-old Rocco, who performed during her MDNA tour last year, is also growing up.

"He's a foot taller, he's getting facial hair, he's looking at girls' butts. It's terrible!" she added.

Lourdes, who is dating Homeland actor Timothee Chalamet, helped Madonna on her tour.

"She worked in the wardrobe department," Madonna said, "She had the very, very unglamorous task of undressing and dressing the male dancers. We had a lot of male dancers. It had its unglamorous moments, they're sweaty and disgusting and they're rude. But she took her job very seriously."

Madonna previously revealed that working with her two children was an "amazing" experience.

"[They got to] travel the world and had to deal with all the ups and downs of doing shows outdoors. Rain, extreme heat, torrential downpours, hail, freezing cold," she told Access Hollywood, "So pushing through any kind of limitations and having the attitude of the show must go on, no matter what [was] good training."