Nancy Sinatra's best throwback photos — and most heartwarming moments with dad Frank Sinatra

Nancy was born in June 1940 to Frank and Nancy Sinatra Sr. née Barbato, the eldest of three siblings. However, their family broke up in 1951 when his affair with Ava Gardner came to light.

The "My Way" singer then tied the knot with the Mogambo actress that year, but he remained close with his daughter, especially once she began following in his footsteps.

By the '50s and '60s, Nancy began studying voice and acting, and made her professional screen debut on The Frank Sinatra Show with her father in 1957.

She was also part of his 1960 TV special The Frank Sinatra Timex Show: Welcome Home Elvis, where she was sent to the airport to receive Elvis Presley, and they duetted together to the song "You Make Me Feel So Young/Old."

Over the decades, the pair collaborated closely, even achieving an international number one hit with their 1967 ballad "Somethin' Stupid."

Frank also appeared in his daughter's 1967 special Movin' With Nancy, alongside other members of the Rat Pack. They remained close till his passing in 1998, and she has written multiple books in tribute to him as well.

Initially, after making TV appearances with her dad, Nancy found it hard to break into the mainstream. That is, until she met songwriter/producer/arranger Lee Hazlewood.

Lee encouraged Nancy to sing in a lower key and abandon the higher tone she had been trained to sing in, thereby allowing her to find a range that suited her voice much better.

After nearly five years in the business, sporting newly bleached blonde locks, she released "These Boots Are Made for Walkin'" thanks to Lee, which became an instant success and was a worldwide number one hit.

The song has created an incredible legacy for itself over the years, having been covered numerous times and been referenced in pop culture endlessly, most recently being sampled by Beyoncé on the Cowboy Carter song "Ya Ya."

Over the years, Nancy continued her success in music and on screen, achieving three more top 10s (including the aforementioned with her father) and receiving four Grammy Award nominations total.

Along with several TV specials and appearances as herself, Nancy starred in a multitude of beach party films in the '60s, and her final film appearance was in the 1968 Elvis musical comedy Speedway. Through it all, she maintained her conservatively sexy mod aesthetic as well.