Billie Eilish drew huge crowds at Amoeba Hollywood in just a few hours notice for an unscripted live performance, according to a report by Variety. Marking the one-year anniversary of her second studio record ‘Happier Than Ever’ the singer took to her hometown record store to perform an acoustic set of selections from her record this Friday. 

Fans crowded every nook and cranny of Amoeba's new Hollywood location to see the singer play a four-song set. Finneas, the singer's brother, producing partner and tourmate, joined her onstage with an acoustic guitar and supporting vocals, according to Variety. 

Variety adds that after opening with 'Billie Bossa Nova' and performing 'TV' off her recent 'Guitar Songs' EP, Eilish left it up to the crowd to decide the next song, which resulted in an impassioned shouting match that settled on 'Getting Older.

At the end of the performance, the singer thanked the crowd and left fans with the most Billie Eilish mic drop possible: "And happy 'Happier Than Ever' anniversary, b****." Between songs, Eilish thanked fans for coming out on very short notice to see her and Finneas play, noting that the one-year anniversary of "Happier Than Ever" also falls on her brother's 25th birthday.

Reflecting on the record's anniversary, Eilish, quoted by Variety, told the crowd: "You guys are just the best. It's been the most amazing year, and you've been so sweet and respectful about this album, and I just love you!"

The duo are in the middle of a month-long break from their 'Happier Than Ever' world tour in support of the record, which kicked off in early February at New Orleans' Smoothie King Center.