Pritchard used the performance before the royals as further ammo in urging Sullivan to put them on his show and helped arrange for Epstein to come make his pitch directly.

PHOTOS: 'Tune In: The Beatles: All These Years'

Epstein persuaded Sullivan not just to put the Beatles on his weekly variety show but to guarantee three appearances. Even more remarkably, Sullivan consented to giving them top billing on the first show even though at that moment they were an unknown quantity in the States.

And vice versa. "We had no idea [Sullivan's show] was that huge," Starr said. "We just thought it'd be a break-in to America. And New York — we were in New York, for God's sakes. It was incredible."

The deal with Sullivan was the ammunition Epstein needed to cajole Capitol President Livingston to release their music in the U.S. and, equally important, to commit to spending $40,000 — a hefty amount in 1963 — promoting the Beatles' new single, "I Want To Hold Your Hand." Capitol slated it for mid-January release, ahead of the Feb. 9 Sullivan show debut.

Things were starting to change: Time and Newsweek magazines carried reports about the Beatles in their issues of Nov. 16 and Nov. 18, respectively. Then all three major American television networks — CBS, NBC and ABC — dispatched film crews to a Beatles' Nov. 16 performance in Bournmouthe, England.

360 PHOTO: Paul McCartney gets his star on the Hollywood Walk of Fame

NBC aired a piece three days later, the group's first national TV exposure in the U.S. A more significant report on the band then aired on CBS the morning of Nov. 22, 1963, shortly before President John F. Kennedy was assassinated in Dallas.

The Beatles story had been slated to be repeated that evening on the top-rated "CBS Evening News with Walter Cronkite," but the JFK news put every other story on the back burner. Eighteen days later, however, Cronkite resurrected the Beatles report in the belief it would give a nation in mourning something to smile about once again.

It did.

Their performance of "She Loves You" on that newscast prompted 15-year-old Marcia Albert of Silver Springs, Md., to contact her local radio station, WWDC in the nation's capital.

"Why can't we have this music in America?" Albert asked.

Deejay Carroll James, who also had seen the Beatles on Cronkite's newscast, responded by inviting Albert to the station to introduce "I Want To Hold Your Hand" before he played it for the first time in the U.S. on Dec. 17. WWDC's phone lines promptly lighted up.

PHOTOS: Daughters of rock stars

Capitol's response? A "cease and desist" letter insisting the station pull the record because the company wasn't planning to release it for almost another month.

It was too late. Other stations had noted the response it was getting in Washington and began playing it. Livingston, quickly realizing the Beatles were out of the bag, pushed up the release date of "I Want To Hold Your Hand" to Dec. 26.

It was a serendipitous move for all concerned.

Teenagers were out of school on winter vacation, many had holiday gift money in their pockets itching to be spent, and radio stations had begun playing the Beatles in heavy rotation. Three weeks later, the Beatles hit No. 1 on the Cash Box singles chart; "I Want to Hold Your Hand" had sold 1 million copies and was showing no sign of slowing down.

The Beatles, who had vowed not to tour the States before they had a No. 1 hit, got the news they'd long dreamed of amid their three-week residency in Paris, which ended Feb. 3. Four days later, they were on a plane bound for the U.S.

PHOTOS: Iconic rock guitars and their owners

Another turning point that affected the group's fortunes stateside was the news conference they held — two days before they'd perform for Sullivan — before a phalanx of reporters and photographers who came to slaughter and instead were conquered by the Liverpudlians' charm and wit.

"They actually said that they came to that press conference to kill us," Starr said. " 'Oh, another band from England.' But because … we shouted back, they loved us. We're from Liverpoool, so you shout at me, I shout at you, that's how it is; I don't care if you are from New York.

"They said that was so great, because everybody comes here and says, 'Oh, it's very nice to be here, and we love it' — and we said, 'Oh, piss off!' or whatever we said. That made the press enjoy us, and that helped," Starr said.

It was more evidence of the dictum often stated by Epstein and various members of the group: If they would be given a chance to be seen and heard, they firmly believed America would fall in love with them.

The various strategies Epstein put in place in the months leading to their arrival to create that chance helped create the frenzy that resulted in a surging throng of 3,000 screaming teens who greeted their plane when it touched down at JFK International Airport.

The fuse had been set, the powder keg primed. All that remained was for Ed Sullivan to step in front of 73 million viewers that Sunday night 50 years ago and strike the match with those five words he uttered at 8:03 p.m. to introduce America to four lads from Liverpool: "Ladies and gentlemen: the Beatles!"

Twitter: @RandyLewis2