The live ambient performance is being held tonight (June 9) as part of BST's free admission four-day Open House midweek event. It will feature music from the band's entire catalogue, including new material, collaborations, solo work, and film scores.
"I'd love to take credit for it but it was their idea," said King. "They called us up and said, 'We're doing this thing, could we do it with you?' And we were like, 'This is what we've been waiting for!' So it's all down to them and they deserve all the credit for it.
"It sold out in seconds. I was a bit worried people everybody thought Sigur Rós were actually playing live, with the speed in which people activated the tickets, but it's going to be a wonderful piece. I think it's going to be incredible."
Tickets were snapped up almost instantly for the sound bath event, which mirrors performances by the Icelandic band at festivals such as Primavera in Barcelona.
"I’ll do them a disservice in my description, but it’s a music-curated meditation and wellbeing session," said King. "It’s going to be a really immersive experience – a multi-sensory activation with everything from music to visuals to incense, with [Sigur Rós] providing the soundtrack."
BST Open House runs from July 8-11 and also includes drag cabaret, open-air cinema nights, live tennis showings, street food and pop-up bars, among other attractions.
"The midweek programme has just gone from strength to strength," added King.