The young US singer's debut, When We All Fall Asleep, Where Do We Go? went straight to number one, with a combined 48,000 sales. It also became the second-fastest selling record of the year, losing only to Ariana Grande's Thank U, Next, which shifted 65,214 units in the first week.
"We worked really hard on this album," Eilish told the Official Charts Company.
Eilish also became the youngest-ever female solo act to top UK album chart, at 17 years, three months, 18 days old – two and half months younger than Joss Stone, who had topped the charts back in 2004.
Three singles from Eilish's record-breaking album have landed in the Top 20 as well, with her latest release, Bad Guy, reaching the number two spot, losing only to Scottish singer-songwriter Lewis Capaldi’s track Someone You Loved.