Already announced to appear are Ramin Karimloo, Lea Salonga, Jodie Prenger, Claire Sweeney, Ruthie Henshall, Lucie-Mae Sumer and singing troupe Collabro.
They will be joined by the 60-piece Heart of England Symphony Orchestra.
On other nights, headliners will include The Village People and the Bay City Rollers (Aug. 5) and Bryan Adams (Aug. 6).
The festival, founded in 2009, has previously featured such artists as Status Quo, Katherine Jenkins, Boyzone, Alfie Boe, Olly Murs, Jason Donovan, Marc Almond and Russell Watson.
To book tickets and for more details, visit http://www.lythamfestival.com/