 Commercially , " Somebody That I Used to Know " is Gotye 's most successful and signature song . It has topped charts in the US , UK , and Australia , as well as 23 other national charts , and reached the top 10 in more than 30 countries around the world . The song has sold more than 13 million copies worldwide , becoming one of the best @-@ selling digital singles of all time . It was also placed at the top of a number of year @-@ end charts by Billboard Magazine ( including the Hot 100 , Adult Pop Songs , and Alternative Songs ) and other record chart companies around the world . 
