Andy Richter has revealed that many of the interior scenes in the 2003 holiday film Elf were shot inside a mental hospital that was still partly in operation. The actor, who played Morris, shared the detail while discussing his new book, Elf Unwrapped: Behind the Scenes of a Modern Christmas Classic.

The production used empty wings at Riverview Hospital in Coquitlam, British Columbia, for locations including the offices, the Hobbs family home and the mailroom, Richter told Us. One wing still housed patients during filming.

Richter said limited studio space and filming locations contributed to the decision to shoot at the hospital, as a “big vampire movie” was also being made. He said he kept to a routine of going between the set, his trailer, the van and the hotel rather than exploring the facility.

He joked about what patients might have made of seeing Will Ferrell in Buddy the Elf’s costume around the hospital during filming. Ferrell spent a month or two there, Richter said, and patients may have spotted him from their windows.

Richter co-wrote the new behind-the-scenes book, which draws on research and interviews with the cast and crew. Ferrell wrote its foreword. The book also recounts casting discussions around Jovie, played by Zooey Deschanel, including the possibility of Selma Blair taking the role and Deschanel auditioning after Katie Holmes was offered it and later dropped out.

Elf Unwrapped: Behind the Scenes of a Modern Christmas Classic is scheduled to be released on November 3.

Sources: Us Weekly.