Abba’s Benny Andersson and Björn Ulvaeus will reunite to celebrate 15 years of the hit show “Mamma Mia!” at this year’s Olivier Awards in London, the show announced Thursday.

Andersson and Ulvaeus will perform with the current London “Mamma Mia!” company in the grand finale.

Also performing is Broadway star and two-time Tony Award-winning actress Bernadette Peters and international opera singer Joseph Calleja.

Calleja is currently singing the title role in the Royal Opera’s production of Gounod’s “Faust,” and will be performing “E lucevan le stele” from Puccini’s “Tosca” at the awards ceremony.

Other performers include the best new musical nominees—“The Book Of Mormon,” “Charlie And The Chocolate Factory,” “Once” and “The Scottsboro Boys.”

Nominees for the highest honor in British theatre include Hayley Atwell, Anna Chancellor, Judi Dench, Joyce DiDonato, Plácido Domingo, Juan Diego Florez, Henry Goodman, Rory Kinnear, Tom Hiddleston, Jude Law and Lesley Manville.

Gemma Arterton and Stephen Mangan will host the Olivier Awards.

The event takes place on April, 13 at the Royal Opera House and will broadcast a full highlights package on ITV.