Following two years army service in West Germany, Elvis Presley was welcomed home extravagantly.

Arriving back home Stateside, the King co-starred in 1960 TV special The Frank Sinatra Timex Show: Welcome Home Elvis.

The programme also happened to be the professional debut of the crooner’s daughter, fellow future music and movie star Nancy Sinatra, who was famously sent to the airport on Frank’s behalf to welcome Elvis home to the USA.

She would later ended up singing a duet on the TV special with her father of You Make Me Feel So Young/Old. And later on in the show, Elvis and Frank performed each other’s songs, Witchcraft and Love Me Tender, a verse at a time.

Then, some seven years later, Nancy and The King were reunited as they co-starred in 1968’s Speedway together, a movie that released 56 years old today.

The musical action movie was shot the year prior, which was also when her Sean Connery Bond theme You Only Live Twice was released. Speedway saw Elvis play NASCAR driver Steve Grayson opposite Nancy’s IRS agent Susan Jacks. Her character’s role involved being assigned to watch over Steve who had $150,000 in debt to pay with any future prize money from racing.

Naturally, this being an Elvis movie meant Nancy’s Susan ended up falling romantically for The King’s character. The film, which was originally planned to star Sonny and Cher, was the last time Frank’s daughter ever acted in a movie. Now 83-years-old, Nancy has shared touching memories of her time on the Speedway set with Elvis, who died aged 42 in 1977.

Speaking previously with PEOPLE, she said: “I know he was the funniest man and probably the most serious man I knew, both people in one. He made me laugh so hard. And at the same time, he would call me late at night to discuss things like the ghetto, and his concern for people in the ghetto. I don’t know if that’s surprising. People who follow his life probably are aware of his sensitivity.”

Nancy and Elvis never dated, but she has admitted in the past that there was some “friendly flirting.” The King had married his only wife Priscilla on May 1, 1967 and filming on Speedway began a few weeks later on June 26.

Elvis and his co-star were so close that he had asked Nancy to throw a baby shower for Priscilla when she began pregnant during filming. And the following year before Speedway was released, The King’s only daughter Lisa Marie Presley – who tragically died in January last year at 54 – was born.