The rock legends' spot was accidentally confirmed by drummer Clem Burke, who recently discussed their busy summer schedule with Foxy Radio, stating: "We’re also doing Isle of Wight Festival and some other festivals… I guess the full list of artists to be playing Glastonbury hasn’t really been announced yet.
"But we are going to be playing Glastonbury, so maybe you’ve got an exclusive there.”
This year's event will mark Blondie's third time at Glastonbury, having last played the festival in 2014 and 1999.
So far, the only officially confirmed artist is Sir Elton John, whose performance will serve as their last ever UK show.
"I couldn’t be more excited to be headlining the Pyramid Stage at Glastonbury 2023 and celebrate the greatest festival in the world!" comments Elton John. "Every week I speak to new artists on my radio show and Glastonbury is often cited as a pivotal moment in launching their careers - the festival’s genuine, enthusiastic support for the best emerging talent is something I’ve long admired. Thank you for having me Emily Eavis for my final UK show - it’s going to be emotional."
Burke isn't the only musician to have let slip that their band will be at Glasto.
Last month Guns N' Roses bassist Duff McKegan told Sirius XM radio, "Glastonbury is going to be iconic for us". The dates of this year's festival tie in with the LA band's British Summer Time at Hyde Park headline show in London on June 30.
Other rumoured acts for Glastonbury include Arctic Monkeys, Lizzo, Lewis Capaldi and Harry Styles.
Also this summer, Blondie will be playing Dog Day Afternoon, which is scheduled to take place in Crystal Palace Park on Saturday July 1, 2023.
The band will be performing as special guests to Iggy Pop, alongside Generation Sex, a UK punk supergroup featuring former Generation X men Billy Idol and Tony James, and former Sex Pistols duo Steve Jones and Paul Cook.
- Here’s how you can watch Glastonbury 2023 no matter where you are