Billie Eilish Celebrates 'Bad Guy' Selling 10 Million Units: 'Forever and Ever Grateful for This Silly Little Song'

The track was featured on Eilish's 2019 debut album "When We All Fall Asleep, Where Do We Go?"

Billie Eilish and Finneas are diamond certified!

On Monday, Eilish revealed on social media that her 2019 smash hit "Bad Guy" received the Record Industry Association of America's highest recognition.

“Bad Guy went diamond………………………. HUUUUUHHHHHHHHHHHHHHH??????????," the Grammy-winner, 21, captioned a photo of herself wearing the all-yellow outfit from the music video. "forever and ever grateful for this silly little song man. love you guys so much its stupid  @finneas"

Finneas — who produced the track — shared her post on his Instagram Stories and added, "This is f—ing crazy actually."

Diamond certifications are granted when singles or albums have sold a minimum of 10,000,000 units.

Eilish released "Bad Guy" in 2019 and it hit No. 1 on the Billboard Hot 100, spending 49 weeks on the chart. It was featured on her debut album When We All Fall Asleep, Where Do We Go? and earned her a Grammy for record and song of the year.

Her latest musical release was "What Was I Made For?" for the Barbie soundtrack. In an interview with Apple Music 1 host Zane Lowe, she revealed how she found the inspiration to write it when experiencing a block.

Eilish and Finneas, 25, saw an early cut of Barbie, with just director Greta Gerwig and a few producers at Warner Bros, she told Lowe. At the end of the screening, Gerwig asked them to "make something" if they were inspired.

Finneas wondered if they should write a "Barbie song," but Eilish rejected that idea. She also realized that writing the track would be different from writing their Oscar-winning title song to No Time to Die. Soon the lyrics to "What I Was Made For?" just "came right out," she said.

"The start of writing this song, the first day of writing, Finneas and I, especially me because it's from my perspective, we were purely only thinking about Barbie," Eilish explained. "I did not think about myself once in the writing process. So that's the full first verse, pre-chorus, chorus, maybe second verse, all in one night."

Eilish said she was "purely inspired" by the movie, its take on Barbie, and how the character would feel. However, she soon realized that the song was really about her.

"I really don't mean this to come off a conceited way at all, but I do this thing where I make stuff that I don't even know is ... like I'm writing for myself and I don't even know it," she said. "It is one of the most incredible things I get to experience in my life. Dude, the next week I was playing it in the car all day and playing it for everybody. And I was like, 'This is exactly how I feel. And I didn't even mean to be saying it.' "

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