West Yorkshire Police were called to Leeds Playhouse at about 11.51am after what are believed to be human remains were discovered at the site during excavation work.
A spokesman for the force said: "Police were called to Playhouse Square, Leeds, at about 11.51am today after what appears to be human remains were discovered at the site during excavation work there.
-> Son killed own mother by repeatedly smashing her with claw hammer"A police scene was established at the site, which was once used as a church burial ground, and tests will be carried out to establish the age of the remains found."
The theatre closed in June following a final performance of Searching for the Heart of Leeds, a new community musical written by the BAFTA winning writer Mark Catley.
It is due to reopen in Autumn 2019 with an entirely new look and layout and it will, from June, bore the new name of Leeds Playhouse - it used to be called West Yorkshire Playhouse.
The theatre has stood on the Quarry Hill site, opposite Leeds bus station, since 1990, but the history of a producing theatre in Leeds stretches further than that.
A theatre for the city, creating work, goes back to 1968 when a group of campaigners convinced a public meeting that this was what Leeds needed. The Leeds Playhouse, as it was then called, was created in a space at the city’s university.