When the houselights dim in downtown White Plains tomorrow night, the theatrical landscape in Westchester will change dramatically – and musically.

Broadway star Robert Cuccioli (“Les Miserables,” “Jekyll & Hyde”) will suit up as Don Quixote in “Man of La Mancha” at White Plains Performing Arts Center in the City Center mall, and the county will have another first-rate home for professional musical theater.

Cuccioli is treading familiar ground, if not familiar boards: He helped put Westchester Broadway Theatre on the map with a 1992 production of Maury Yeston and Arthur Kopit’s “Phantom,” which ran an unheard-of nine months at the Elmsford dinner theater.

By coincidence, Cuccioli was cast in “La Mancha” just as WBT was readying a revival of “Phantom,” which is now on hiatus while “A Christmas Carol” plays a holiday run.

Cuccioli’s role in inaugurating the new venue is a testament to bad luck, good luck and good timing.

He was set to play opposite Randy Quaid in the Broadway production of “Lonestar Love” this fall. The twangy rendition of “The Merry Wives of Windsor” was slated to open Monday, but it closed during its tryout in Seattle. That was bad luck for Cuccioli, who had turned down other jobs, expecting to be on Broadway.

As soon as that closing notice went up, Cuccioli’s phone rang with an offer from Jack W. Batman (BAT-min), the director of WPPAC. That was good timing on Batman’s part and good luck for Cuccioli.

Batman told the star he was turning the center into a home for Broadway-caliber musicals. Would Cuccioli consider appearing in the first production, playing Cervantes and Quixote?

Would he ever.

“Thank God,” Cuccioli says, “because when something like that happens [a Broadway-bound show closing out of town], you’re looking at a wasteland of work ahead of you.”

“I was grateful for the phone call – and also to be able to do something that I’ve wanted to do ever since I got into this business. I’ve always loved this show, the music and the role.”

“Man of La Mancha” is Miguel de Cervantes’ timeless story of an infectiously optimistic dreamer who believes he’s a knight-errant. It’s set to Mitch Leigh’s music, with lyrics by Joe Darion and a book by Dale Wasserman.

The show opened on Broadway on Nov. 22, 1965, and ran for nearly six years – 2,328 performances. It won Tony Awards for composer and lyricist Leigh and Darion, actor Richard Kiley, scenic designer Howard Bay and director Albert Marre, and it was named best musical of 1966.

In the musical, Cervantes the playwright is jailed for questioning by the Inquisition. Once in the dungeon, he puts on makeup and tells the story of the aging Alonso Quijano, who takes on the persona of Don Quixote de la Mancha, a knight-errant traveling the Spanish countryside with his squire, Sancho Panza, seeking to right all wrongs.

The songs include “I, Don Quixote,” “Dulcinea” and the anthem “The Impossible Dream.”

“The music is certainly a major factor in the show – and everyone certainly knows the music, so it’s extremely important,” Cuccioli says. “But the story in between the songs is equally as powerful.

“I see this as a play with music, not your typical musical. If you look at the original teleplay on which this is based – called ‘I, Don Quixote’ – it’s this script, word for word. And there’s no music in that. They put music to a play. That’s how I view it.”

Cuccioli admires the message and the method of “Man of La Mancha.”

“One of the beautiful things about this piece is that everybody in the prison has been transformed in some way so that when Cervantes leaves the dungeon to face his fate with the Inquisition, they are all transformed by this story of Don Quixote that he presented to them.”

Some might look at Quixote – who dreams windmills into giants – as a hopelessly befuddled old man. Cuccioli takes a longer view.

“It’s a matter of when the world seems insane, who can really say what madness is? Especially at a time now, it’s so appropriate. The world looks like it’s in the hands of madmen, so what is sanity?”

The actor says the richness of the character lies in his ability to see deep within those around him.

“He is pure light. He’s saying not to allow your eyes to be clouded over with seeing the bad in mankind and the world. What allows him to change people so much is that he is able to envision that kernel of goodness within people that they have armored over for whatever reason throughout their lives. Everyone does that in a different way, and he bursts through that armor and sees that.”

Now that he’s had a chance to don the Don’s armor, how does the part fit?

“I wish I had longer to rehearse,” he says with a laugh. “It’s a role I’ll be honing the rest of my life, for as long as I can play it.”

Landing a Broadway star like Cuccioli is a coup for Batman and his new theater. This fall, Batman announced plans to present nothing but musicals in the 400-seat venue, and turn it into professional, Equity-contract theater. The main-stage season will continue with “Ain’t Misbehavin’ ” in February and March and “How to Succeed in Business Without Really Trying” in April and May.

But first, there is “La Mancha,” an Everest of a part. Actually, two parts.

“They’re very difficult – Cervantes and Quixote. Quixote, in particular, is very difficult to find. I’ve been throwing spaghetti at the wall and seeing what sticks, and the audience will help me find some more factors to it.”

Cervantes becomes Quixote in full view of the audience – pasting on bushy eyebrows and a goatee. Once the makeup is on, it stays on, Cuccioli says, so he’ll have to find a way to convey that he’s talking as Cervantes, even though he’ll look like Quixote.

“Hopefully, lighting will help people know where we are at that point, and my energy will also help people know where we are in the story.”

“The voice was not that difficult. But the physicality is a challenge, trying to play an 80-year-old man who really isn’t 80 years old. He’s young at heart, so the body and legs may be weak, but the heart is strong.”

Playing two characters is something he’s done before: When he played the title characters in “Jekyll & Hyde” on Broadway – and on tour for two years before Broadway – he achieved the transformation from doctor to sinister creation with a simple flick of his hair.

Every Quixote has his Aldonza, the prostitute he fancies as his Dulcinea, his sweet love.

“Aldonza undergoes the biggest change,” Cuccioli says. “He sees the light that she dimmed, the inner child, the ember that is still glowing.”

Rosina Hill plays Aldonza.

“She’s wonderful,” Cuccioli says. “She has a glorious voice and a great, earthy quality. She’s perfect.”

Carlos Lopez plays Sancho Panza, Quixote’s squire.

“He’s a blast. We have great chemistry, a good partnership together. Actors are able to form bonds immediately. You find a way to get those relationships going. You have lunch together, you talk. With Carlos, we have the same twisted sense of humor, so it works out very well.”

Asked if he feels the burden of helping to put a venue on the map, Cuccioli blanches a bit, then smiles.

“Not until just now,” he says with a laugh.

“They’ve chosen an excellent show to start this with. It’s something that everyone knows. That adds a bit of pressure on me because of that. Many people saw Kiley do it; many people saw [Robert] Goulet do it; and Brian [Stokes Mitchell]. So there’s that kind of pressure. In the end, I just try to do the best job I can do, and hopefully, that will be what everyone’s looking for.”

When people think of Don Quixote, they invariably think of windmills. Not so for the man who’s about to play him.

“The windmill is not a big issue for me,” Cuccioli says. “I view this as a journey. I just get on the train and start with it. I can’t start thinking about what’s coming up. I just let it take me wherever it goes.”

People also think of the song “The Impossible Dream,” which Cuccioli sees as “more than just the notes.”

“All of the songs are acting exercises.”

So after “La Mancha,” what’s his next dream role, a part he’s always wanted to play?

“I like to say that it hasn’t been written yet,” he says. “I like to create new works.”

“Man of La Mancha”
Where: White Plains Performing Arts Center, 11 City Place, White Plains.
Finding it: Take Mamaroneck Avenue to the intersection with Main Street. Turn right and, at the first light, turn right into the City Center parking garage. Go to the top level. Park and take the walkway across to the PAC, which is next to the movie theater.
When: Through Dec. 16. At 8 p.m. Thursdays, Fridays and Saturdays; at 2 p.m. Sundays.
Tickets: $35 to $60 for each show; three-play subscriptions from $75 to $150.
Call: 914-328-1600.
Web: wppac.com.
Next: “Ain’t Misbehavin’ ” is Feb. 28 through March 16; “How to Succeed in Business Without Really Trying” is April 24 through May 11.