Billy's Boffo Broadway Sales

And the new king of Broadway is . . . Billy Crystal (search).

With a month to go before it begins previews at the Broadhurst Theatre, "700 Sundays" (search) — Crystal's autobiographical one-man show about growing up in New York — has already sold more than $6 million worth of tickets, The Post has learned.

That's the highest advance of any production this fall, and the highest advance for any nonmusical play in Broadway history.

If ticket sales continue at this pace, Crystal's show should be able to bank between $9 million and $10 million by the time it plays its first preview Nov. 12, theater sources estimate.

A $10 million advance is considered extremely strong for a musical. For a one-man show, it is unheard of.

As both the star and the chief backer of the show, Crystal stands to make about $5 million for his four-month run, theater sources estimate. That's a weekly paycheck of more than $250,000, which would make Crystal the highest-paid performer in Broadway history.

Larry Magid, who is co-producing the show with Crystal's wife, Janice, declined to discuss the advance in detail, but said: "We are very, very pleased with sales at this point. We were always confident that people would want to see Billy on Broadway in the right vehicle."

None of the other one-person shows scheduled to open this fall can touch "700 Sundays." Advances are said to be well under $500,000 for Eve Ensler's, Mario Cantone's (search) and Dame Edna's shows.

Sales are especially weak for Whoopi Goldberg, who trots out her 1980s routine at the Lyceum next month.

"Billy Crystal is selling so well, he's sucking business from everybody else," one producer noted.

"700 Sundays," which opens Dec. 5, is scheduled to run only until March 6, although it could be extended into the summer.

"He is running a very lean operation," one theater source said of Crystal's foray onto Broadway. "There are no frills."

In "700 Sundays," Crystal will recount his childhood on Long Island and his relationship with his father, who managed the Commodore Music Store.