Few Hollywood mother-and-daughter pairings are as iconic as Judy Garland and Liza Minnelli. Both are just as well known for their work on screen as on stage; both were successful singers and dancers as well as actresses; and both have been awarded Oscars—Garland a special Juvenile Award in 1939, and Minnelli the Best Actress award for her role in Cabaret in 1972. Not only that, but Liza’s father—the director and producer Vincente Minnelli—was also an Oscar winner, having picked up the Best Director award for his 1958 movie Gigi.

Vincente Minnelli and Judy Garland met while filming Meet Me In St. Louis in 1944. Despite an initially frosty relationship between them, they soon became close and married the following year. Liza was born a year after that in 1946, and—just like her mother before her—made her movie debut in childhood. In the final scene of Garland’s 1949 musical In the Good Old Summertime, a 3-year-old Liza briefly joins the rest of the cast on screen in an uncredited role as Garland’s character’s daughter.

At least, that’s the official story of Liza Minnelli’s film debut. In fact, by the time In the Good Old Summertime Minnelli was already something of a screen veteran.

In 1946, MGM released a musical biography of the renowned composer Jerome Kern entitled Till the Clouds Roll By. Directed in part by Garland’s husband Vincente Minnelli, Garland was brought in to portray real-life dancer and 1920s Broadway star Marilyn Miller. But by the time Garland’s filming schedule came through, there was a problem: She was pregnant.

Fearing that she would lose out on the role, Minnelli struck a deal with MGM. If they would agree to film all of Garland’s scenes together, as soon as possible, he would direct her portion of the movie. Incredibly, MGM agreed, and with a hastily reworked filming schedule put in place—and with a combination of inventive costume choices and close-up shots used to cover up Garland’s baby bump! —filming went ahead.

Ultimately, Liza Minnelli’s somewhat unofficial big screen debut was in Till the Clouds Roll By—five months before she was even born.