Hanson thrilled Sydney Opera House audiences by singing the Bee Gees’ “Too Much Heaven” acapella without microphones! The three brothers laid their instruments down after the band ended its set for a more intimate performance. The boys’ amazing voices and exquisite harmonies reminded everyone why they were so famous.

As children in the early 1990s, Hanson and his brothers formed an acapella band and recorded vintage rock hits. Since the Sydney Opera House was constructed to allow orchestras to play without microphones, it was ideal for such a performance. The 2.5 million-view YouTube performance is below.

Hanson fan Nicole Thompson said the performance was the only encore on the String Theory Tour, which promoted their studio album of the same name. Thompson said supporters were “spoiled rotten with this unique treat from the guys.”

The String Theory record, arranged by David Campbell, included Hanson’s work with the Prague Symphony. The tour featured orchestral interpretations of the band’s music. Acapella performances by Hanson include their 1997 Music Awards rendition of “MMMBop,” which you can watch below.