Jazz icon Ella Fitzgerald’s voice is recognized by millions around the world. But few know about her career-defining friendship with Marilyn Monroe, to whom Fitzgerald said she “owe a real debt.”

While touring in the ’50s under the management of Norman Granz, Fitzgerald, like many African-American musicians at the time, faced significant adversity as a result of her race, especially in the Jim Crow states. Granz was a huge proponent of civil rights, and insisted that all of his musicians be treated equally at hotels and venues, regardless of race.

Despite his efforts, there were many roadblocks and hurdles put in to place, especially for some of the more popular African-American artists. Here is one story of Fitzgerald’s struggles (as written in chicagojazz.com):

Once, while in Dallas touring for the Philharmonic, a police squad irritated by Norman’s principles barged backstage to hassle the performers. They came into Ella’s dressing room, where band members Dizzy Gillespie and Illinois Jacquet were shooting dice, and arrested everyone. “They took us down,” Ella later recalled, “and then when we got there, they had the nerve to ask for an autograph.”

Across the country, black musicians, regardless of popularity, were often limited to small nightclubs, having to enter through the back of the house. Similar treatment was common at restaurants and hotels.

Enter Marilyn Monroe

During the ‘50s, one of the most popular venues was Mocambo in Hollywood. Frank Sinatra made his Los Angeles debut at Mocambo in 1943, and it was frequented by the likes of Clark Gable, Charlie Chaplin, Humphrey Bogart, Lauren Bacall and Lana Turner.

Fitzgerald was not allowed to play at Mocambo because of her race. Then, one of her biggest fans made a telephone call that quite possibly changed the path of her career for good. Here, she tells the story of how Marilyn Monroe changed her life:

“I owe Marilyn Monroe a real debt … she personally called the owner of the Mocambo, and told him she wanted me booked immediately, and if he would do it, she would take a front table every night. She told him – and it was true, due to Marilyn’s superstar status – that the press would go wild.

“The owner said yes, and Marilyn was there, front table, every night. The press went overboard. After that, I never had to play a small jazz club again. She was an unusual woman – a little ahead of her times. And she didn’t know it."

Learning from Fitzgerald

Fitzgerald had an influence on Monroe as well. Monroe’s singing had a tendency to be overshadowed by dress-lifting gusts of wind and the flirtatious “Happy Birthday, Mr. President,” not to mentions her movies and marriage to Joe DiMaggio.

But years prior to the Mocambo phone call, Monroe was studying the recordings of Fitzgerald. In fact, it was rumored that a vocal coach of Monroe instructed her to purchase Fitzgerald’s recordings of Gershwin music, and listen to it 100 times in a row.

Continued study of Fitzgerald actually turned Monroe into a relatively solid singer for about a decade, but those years were overshadowed by her famous birthday tribute song to JFK in 1962.