The Queen guitarist joined in with a performance of the We Will Rock You musical at the venue in Southsea.
Audiences were wowed by the unexpected appearance of Mr May.
He performed a guitar solo during his time on stage.
If you missed out on the performance last night, here are our best photos.
You can see them in our galley below.
Make sure to click through all the pages!
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9. Brian May
The crowd reacts as Brian May makes his surprise appearance. Picture: Habibur Rahman Photo: Habibur Rahman
10. Brian May
Brian May makes an appearance at the performance of We Will Rock You at the Kings Theatre, Southsea last night. Picture: Habibur Rahman Photo: Habibur Rahman
11. Brian May
Brian May makes an appearance at the performance of We Will Rock You at the Kings Theatre, Southsea last night. Picture: Habibur Rahman Photo: Habibur Rahman
12. Brian May
Brian May makes an appearance at the performance of We Will Rock You at the Kings Theatre, Southsea on Tuesday. Picture: Habibur Rahman Photo: Habibur Rahman