The most diverse Hawaii Shakespeare Festival in the event’s history continues Monday with the opening of “Dromio and Juliet,” a production that Shakespeare could have envisioned but certainly didn’t write. Incorporating improv comedy, it’s described as “a high-octane mash-up of ‘Comedy of Errors’ with ‘Romeo and Juliet,’ featuring forbidden love and two households.”

Forbidden love is a central theme of “Romeo and Juliet,” and “A Comedy of Errors” is about two sets of identical twins who were separated at birth and don’t know that their twin is alive. HSF co-founder Tony Pisculli directs this “mashup,” presenting it as it might have been performed 400 years ago in Italy — as Italian “commedia dell’arte.”

“It’s a little jam-packed this year, but we did this successfully in 2015,” Pisculli said with a chuckle. “Two years ago it was ‘Romeo and Juliet’ plus ‘Tempest Tempest Tempest.’”

Doing a “regular” production of “Romeo and Juliet” this year made doing another mashup/improv comedy show “too good an opportunity to pass up,” Pisculli said. Most of the actors from the 2015 production are back for this one.

Commedia dell’arte adds another layer to the improv-based staging. In mid-16th century Italy, commedia dell’arte started as a form of outdoor theater when people across the Italian peninsula spoke mutually unintelligible dialects. Companies developed stock character types — foolish old men, pompous military officers, cunning or inept servants, know-it-all doctors, sincere but impossibly naive lovers, and rich men who are greedy despite already having great wealth — whose masks, costumes and distinctive mannerisms could transcend language barriers. They did this so well that commedia dell’arte became popular across much of Europe for two centuries.

Pisculli introduced commedia dell’arte to contemporary Hawaii in 1998 when he presented “Guano dell ‘Amore: A Modern Commedia,” an original play he wrote after spending a summer in Italy studying with commedia dell’arte teacher and mask maker Antonio Fava. Pisculli presented a second original commedia dell’arte show, “Zanni Got His Gun,” in Honolulu in 2001.

“It’s one of my favorite forms of theater,” he said. “There is no script and none of what the actors say is preplanned, but there is a very detailed scenario.”

And here is where the scenario begins: Antipholus Montague (Garrick Paikai) and Dromio Montague (Christina Uyeno) travel from Ephesus to Verona — the home of Antipholus Montague and Dromio Montague (also played by Paikai and Uyeno). Other residents of Verona include Andriana Capulet (Stephanie Keiko Kong), Luciana Capulet (Steph Sanchez), Juliet Capulet (Judithanne Young), Tybalt Capulet (R. Kevin Doyle) and a nurse (KC Odell). Each member of the cast plays two characters, except for Diana Wan, who plays three.

Be prepared for broad physical comedy, colorful costumes, double entendres, gibberish, mask, non sequiturs, one-liners, sight gags, slapstick and — of course — Shakespeare.

“We brought in (HSF co-founder) R. Kevin Doyle and Steph Sanchez, so now with Garrick (Paikai) we’ve got three of the members of (the old) Mental Tilapia (improv group),” Pisculli notes. “And we have Stephanie Kong and Christina Uyeno. It’s one of the funniest shows I’ve ever done, all the way back to ‘Guano dell ‘Amore.’”