One concert will be announced on Monday morning, with another possibly later the same day.
The theatre's promoters, and Scarborough Council, are keeping fingers crossed that the easing of Covid-19 restrictions will mean the programme can go ahead.
The pandemic had threatened to cancel shows this summer, but as restrictions begin to ease, rescheduled dates have now been announced.
Two of this year's hoped-for acts have moved to 2022. They are Lionel Richie, moved to Saturday July 2 2022, and Lewis Capaldi moved to Thursday July 7 2022.
Other concerts for 2021 have been moved to later in the summer.
Tickets already purchased will remain valid for the new dates. Ticketmaster will contact customers to confirm details.
Here's the revised 2021 line-up so far:
Crowded House Tuesday 8 June 2021
The Beach Boys Sunday 13 June 2021
RuPaul's Drag Race Sunday 20 June 2021
Bryan Adams Thursday 1 July 2021
Kaiser Chiefs Sunday 8 August 2021
Westlife Tuesday 17 August 2021
Nile Rodgers & CHIC Friday 20 August 2021
Keane Saturday 21 August 2021
Olly Murs Friday 27 August 2021
UB40 featuring Ali Campbell & Astro Saturday 28 August 2021
Snow Patrol Friday 10 September 2021
Duran Duran Friday 17 September 2021
Lionel Richie Saturday 2 July 2022
Lewis Capaldi Thursday 7 July 2022