Chicago audiences have heard the most important stage works of Gaetano Donizetti — “Lucia di Lammermoor,” “L’Elisir d’amore” and “Don Pasquale” — more times than they care to recall. As for the rest of the Italian bel canto composer’s approximately 70 operas, there are numerous hidden gems that, for various reasons, are sorely neglected by opera producers here, there and everywhere.

Beginning this weekend, Chicago Opera Theater is narrowing the local Donizetti gap with a double bill of one-acters — one from the beginning, the other from the end, of the composer’s career — that almost certainly have never been staged professionally in the city: “Il Pigmalione” (“Pygmalion”) and “Rita.”