“Crazy Rich Asians” director Jon Chu sent a heartfelt letter to Coldplay to convince them to let him use one of their hit songs in the film’s soundtrack — but its title stirred up controversy.

In an interview with Quartzy, Chu explained how he wanted to “take hit American songs and make them Chinese.” However, he hit a roadblock when he tried to reach out to the British band in an effort to translate “Yellow” from English to Mandarin. Even the film’s studio, Warner Bros., was reluctant to use the track, as the word “yellow” has been use as a slur for Asians and the color of their skin — most notably in the phrase “Yellow Peril,” referring to a fear of Asian immigrants stealing jobs from U.S. workers in the late 19th century.

“They were like, ‘Whoa, we can’t do that, what do you think people will say?’ And I told them, ‘Well, a white director couldn’t do it,'” Chu said.

Also Read: Don't Be Surprised If 'Crazy Rich Asians' Blows Away Box Office Expectations

The studio eventually relented, but Coldplay outright rejected him, Chu recalled in the interview. After all, the band had previously been chastised for music videos that appropriated broadly Asian outfits and motifs, such as “Princess of China” and “Hymn for the Weekend.” Not to be dissuaded, Chu sent the band a letter laying out his “complicated relationship” with the word but his love for the song:

“For the first time in my life, it described the color in the most beautiful, magical ways. The color of the stars, her skin, the love. It was an incredible image of attraction and aspiration that it made me rethink my own self image.”

Within the hour, Coldplay granted him permission to use “Yellow,” and it became the final track heard in the film. Chinese-American singer and “The Voice” contestant Katherine Ho belts the lyrics in Mandarin in her cover of the song.