A 2000s rock band has scrapped its tour dates celebrating a special anniversary.

The Fratellis, a Scottish indie rock group known for hits like “Chelsea Dagger” and “Henrietta,” planned to mark two decades since their 2006 debut album “Costello Music.” More than a dozen concerts across the UK were already sold out in February and March, but they are now being postponed due to “illness in the band.”

New show dates have not been announced, but promoters said tickets purchased for the original dates would be valid for the rescheduled shows. Details about potential refunds were not immediately announced.

In a statement, the band said lead singer-guitarist Jon Fratelli, whose real name is John Lawler, is “unable to perform right now due to ongoing health issues.”

“With the tour so close it breaks our musical hearts to take this decision but in light of medical advice that Jon takes time to recover it’s the only sensible option,” The Fratellis said.

The Glasgow rockers said they previously faced “a far more serious medical obstacle that should have ended our dream there & then” shortly after forming at the end of 2004. They didn’t elaborate on what health problems they faced then or currently.

“With a wee bit of time we’ll do now what we did then… whatever it takes to get back onstage as quickly as possible, playing music for anyone who loves our thing as much as we do,” the statement continued. “We were blown away by the reaction to this tour and can only promise that we are as disappointed as you at having to wait a little longer to celebrate Costello Music’s 20th Birthday. We’ll do everything possible to announce the new dates ASAP… We love you all.”

The Fratellis are still scheduled to play all summer shows, including festivals in England, Scotland and Wales. Their next performance will tentatively be May 2 at the MacMoray Easter Festival in Elgin, Moray.

The band, named after the villainous family in “The Goonies,” is best known for its 2006 debut album, “Costello Music,” which went to No. 2 in the UK and No. 48 in the U.S. They toured in North America with The Police, won Best British Breakthrough Act at the 2007 BRIT Awards, and had music featured in movies and TV shows like “Pitch Perfect,” “One Tree Hill,” “Hot Fuzz,” “Community,” “Gossip Girl,” “She’s Out Of My League,” “90210″ and ”Chuck.”

The Fratellis songs like “Henrietta,” “Chelsea Dagger,” “Flathead,” “Whistle for the Choir” and 2013’s “She’s Not Gone Yet But She’s Leaving” remain popular today with more than 800 million combined streams on Spotify. The alternative rock group released its sixth album in 2021.