David Frost: Are you really saying that the president can do something illegal?
Richard Nixon: I'm saying that when the president does it, that means it's not illegal.
David Frost: ...I'm sorry?
The Sydney harbor scenes have the backdrop of the opera house. The buildings (aka "The Toaster") beside the opera house were not completed until 1998. The film was set in 1976-77.
Both Frank Langella and Michael Sheen played their respective roles in the original Broadway production.