The first photo showed the “Birds of a Feather” singer as a child wearing a rainbow sequin dance costume and white Converse sneakers. She posed in a room filled with Justin Bieber posters. The post then moved to a whiteboard where a young Eilish had rewritten the lyrics to Aqua’s 1997 song “Barbie Girl” with a purple marker. She also added details about Bieber’s birthday and his birthplace in Canada.“I’m a Bieber girl,” she wrote. “In a Bieber world, it’s Biebertastic, let’s Bieber blast it, Bieber flips his hair, wears purple everywhere, it’s a Bieber nation, thank god for his creation! Come on Bieber spread the FEVER!”

Billie Eilish’s ‘One Less Lonely Girl’ moment

The rest of the Instagram slides showed Eilish across the years wearing Bieber’s merchandise. She also included Bieber-fever themed memes. The final slide featured a young Eilish dancing to Bieber’s 2013 song “Confident.”The post came after Bieber invited Eilish, who has long called herself a Belieber, onstage during his Coachella headlining set on April 18. He brought her out midway through his 2009 hit “One Less Lonely Girl.”The next day, Eilish showed fans that she was still emotional over the surprise. She posted a selfie on Instagram Stories with red eyes and wrote, “Can’t stop crying.”Her mother, Maggie Baird, also shared a heartfelt Instagram post after the performance. She called it “one of the most touching moments ever.”“We watch our children develop these deep deep connections to artists who move them and usually there’s nothing in our power to do… Watching this crazy unimaginable dream come true over many years is so incredible,” she wrote.The throwbacks turned the Coachella cameo into a full-circle moment for Eilish and Bieber’s fans.