Billie Eilish wrote 'No Time To Die' after her first ACL Fest

Billie Eilish is returning to the Austin City Limits Music Festival for the event's second weekend after an incredible opening weekend performance.

Her W2 set lines up with the theatrical release of "No Time To Die," the 25th film in the James Bond franchise.

The film stars Daniel Craig in his fifth and final outing as Agent 007, the return of Léa Seydoux as Bond's love interest Madeline, and Oscar-winner Rami Malek as the villain Safin. The movie is set to premiere in theaters on Friday, Oct. 8, a day before Eilish returns to the stage in Austin.

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Billie Eilish and brother Finneas O'Connell co-wrote this James Bond theme song

Writing the theme song for a Bond film has been a bucket list item for Eilish. Along with her brother Finneas O'Connell, the two wrote the song over the course of three days in 2019.

According to an interview with the siblings in Vulture, the writing took place in Texas in October 2019 "on a parked tour bus in the lower levels of an echoey arena." 

O'Connell couldn't recall if they were in Dallas or Houston at the time but said the song was written on tour in Texas.

A look at Eilish's concert schedule for that month showed she performed for the first time at ACL Fest on Saturday, Oct. 5, and then made tour stops in Tulsa, Dallas and Houston before returning to the second weekend of ACL Fest on Saturday, Oct. 12. She was two months away from turning 18 years old at the time.

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O'Connell told Vulture the two had been stuck with "bad writer's block" on the song for a while. He gave up his guitar for a piano in the green room of an arena on the tour and came up with the opening to the song.

“Immediately we were like, ‘Ohhhh.’ It just suddenly made sense. And then we wrote the rest," Eilish said.

The song features a full, 70-piece orchestra playing a composition by the legendary Hans Zimmer, with input from Eilish and O'Connell.

Zimmer said the track provided to him by the siblings was "a perfect movie song."

"In its quietness, somehow, you have a huge landscape in front of you," Zimmer told Vulture.

Ahead of Bond movie release, music video for No Time To Die debuts

While the song has been out for months, the music video for the song was released on Eilish's YouTube channel a day before she headlined the opening weekend of ACL Fest.

The video contains clips from the forthcoming film, giving viewers a sampling of what could be in store in the highly anticipated movie.

The music video has been viewed more than 45 million times in first four days since it's premiere. You can watch it here: