It’s time to mount an invisible horse and take a trip to Camelot – or at least Washington. If you’re ready to quest for the Holy Grail, visit Washington’s National Theatre Tuesday night when Monty Python’s Spamalot rolls into town.

The 2005 Tony Award winner for Best Musical previously appeared at the National Theatre in 2006. But as with any touring musical, roles have changed and acts have been tweaked. Tuesday will be the Washington area’s first chance to see Esther Stilwell take on the role of The Lady of the Lake.

Stilwell has been with the touring cast since January 2006, when she started as an understudy before taking over the role this spring, she said.

“I was only covered to learn this one role, to go onstage if [the main actress] got sick or went on vacation,” Stilwell said. “It gave me a lot of time to think and surf the Web, but I couldn’t complain, because I was getting a paycheck and it was my first show as an Equity Actors Union member.”

Ben Davis is also new to the cast, having jumped into the roles of Sir Dennis Galahad, The Black Knight and Prince Herbert’s Father in October.

Spamalot is based loosely on Monthy Python and the Holy Grail, the film that helped skyrocket the careers of Python members John Cleese, Eric Idle and Terry Gilliam. Idle wrote Spamalot’s book and lyrics, which “lovingly rips off the motion picture.” Like Holy Grail, Spamalot is a parody of King Arthur’s legend; it differs, however, in its parodies of Broadway and additional characters such as Stilwell’s Lady of the Lake, who isn’t in the film.

“It takes a lot of the parts from [the film] and incorporates it in the show,” Davis said. “But then it does some things that make it a musical. It pokes fun at a lot of musicals and makes fun of the genre. … A lot of people tend to put Monty Python into this place where you either get it or you don’t, but I don’t see that for the show itself.”

Stilwell said she actually prefers Spamalot to the Holy Grail.

“That’s my version; that’s the version with singing, which I enjoy,” she said “There’s something maybe more pure about the movie, because it was the one time they were all together. People who love Python love the show; they aren’t let down. People who don’t know Python still love the show, especially people who love musicals.”

In true Python style, the musical offers chances for actors to improvise during the show.

“There are the scripts and then, within that, there are little pieces where you can improvise,” Davis said. “And within that, there are little characters that can improvise, like the Knight of Need.”

“I have little moments where there’s always improvisation,” Stilwell added. “I’ll admit, I tend to be very safe – I’m not one of those really brave people who do improv classes and improv comedy. Other actors have bits they break in, like pop culture references.”

One of Stilwell’s favorite parts of the show is when she gets to imitate different legendary musical voices, with vocal send-ups to Julie Andrews and The Phantom of the Opera, among others, she said.

“It’s kind of all over the map, so I’m never just singing with my natural voice,” Stilwell said. “I’ve always loved singing different styles; I love jumping in and imitating other people’s voices.”

For Davis, who has performed in more serious roles in Les Misérables and Baz Luhrmann’s La Boheme, Spamalot is a different animal.

“I think [Les Misérables and La Boheme] are so revered and referential,” Davis said. “Monty Python, among some, is also [revered], but in a totally different way. It’s kind of one of those shows where people come and they know they’re going to have a good time. And, to get that kind of response from the audience, there’s nothing else like that.”

Monty Python’s Spamalot opens at the National Theatre Tuesday night. The show runs through Jan. 6. Tickets range from $46.50 to $176.50.

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