Was it really that long ago? Paul Blake hardly could believe that his musical stage adaptation of "Roman Holiday" debuted in St. Louis in 2001. But as the producer/director/writer began to recount the show's travels since then, he admitted that the arithmetic added up.

"The Italian thing happened and that took a lot of time," Blake said by phone. "And then 'White Christmas' came in and took a lot of time. Then this English producer showed up and we got lost on other things."

We will get to "the Italian thing" and the "English producer" and the rest in a minute. What matters now is that Blake's retooled "Roman Holiday" -- with songs by Cole Porter -- opens Friday at the Guthrie Theater. Blake's revisions are so thoroughgoing that the Guthrie is billing this "brand-new musical" as an American premiere.

"It's very different from the show that went up at the Muny," said director John Miller-Stephany of the 2001 production on St. Louis' massive outdoor summer stage. "The song list is different, a lot of the ideas are different."

New York actors Stephanie Rothenberg and Edward Watts play the roles made famous by Audrey Hepburn and Gregory Peck in the 1953 romantic film comedy. The Guthrie cast includes familiar names Michelle Barber, Christina Baldwin, David Anders and John Skelley.

"It will be interesting to see the audience in front of it because this is easily 30 percent a new script, if not more," Blake said.

Blake ran the Muny for 22 years, stepping down after last summer's season. In addition he worked for Paramount Pictures, taking movies that the studio owned and turning them into stage musicals. "Irving Berlin's White Christmas" was his first project and then he took on "Roman Holiday" in 2001. He used the film's framework -- a princess sneaking out for a frolic around Rome with an American expatriate -- and felt that Porter's music would be the right complement.

"I got to the song 'Easy to Love' and the end of it, the lyric says: 'But you can't see your future with me, and you'd be, oh, so easy to love.' And I said, that's the story -- they can't see their future with each other because it doesn't work," Blake said.

He dug into the composer's voluminous catalog and found enough songs that he felt "it's like he wrote them for the show."

Long journey into Guthrie

Following the St. Louis staging, an Italian producer picked up Blake's script, added some songs from a contemporary composer and launched "Vacanza Romane."

"Nothing runs for very long in Rome, so they would play three months, then tour, take the summer off and then go back into Rome and tour again -- and that went on for three years," Blake said.

An English producer then asked for the rights and "screwed it up totally," said Blake, who at this point was positioning "White Christmas" for a premiere in San Francisco, a subsequent tour and a limited Broadway run in 2008. (The Ordway staged the show in 2006 and 2008.) In October 2010, Blake had overhauled the "Roman Holiday" script and changed the score for a developmental production in New York. Miller-Stephany asked to see the script and liked it.

"I thought it was a fantastic idea to use Cole Porter songs, because they reflect the screenplay so well," Miller-Stephany said. "They are literate, sophisticated, funny, heartfelt and at the end of the day heartbreaking."

Miller-Stephany gave his ideas to Blake and the project continued to take shape -- through a Guthrie workshop last winter and during recent rehearsals.

"John is a very good dramaturg," Blake said, "so we looked at ways of fixing the script and where the songs should go."

The basic premise of "Roman Holiday" would not pass muster today. The princess dashes through a giddy romance with American reporter Joe Bradley. It is the sweetest, lightest lark, but it is doomed to end -- for in 1953 a princess marrying a commoner was unthinkable. Grace Kelly broke that barrier a few years later with Prince Rainier in Monaco. It is almost commonplace now, and two years ago Swedish Crown Princess Victoria married her personal trainer.

Miller-Stephany acknowledges the retro feel to "Roman Holiday," but he sees the show more as a timeless fairy tale.

"There is this 'Once Upon a Time' quality," he said. "Two people have a profound effect on each other over 24 hours and it's a relationship that changes their lives. It is a substantially romantic idea."

Blake always has hoped to get "Roman Holiday" into New York. He feels the work he and Miller-Stephany have done gets him much closer to that goal. He said there is interest and financing, but he wants to find the right medium-sized Broadway house.

"We have every intention of moving into New York," Blake said. "I've talked to [Broadway powers] the Nederlanders; they're interested in it. I think Jimmy [Nederlander] Junior is coming out to see it. It's just a matter of timing right now and finding the right theater."