The official Prince tribute on Thursday in St. Paul sounds like a typical Prince production: Grand ideas, false starts, last-minute shakeups and a big-buck gamble that it’ll be something special.

Pop star/guitar hero John Mayer dropped out on Tuesday due to a scheduling change. But that seems minor compared to the all-star event’s dramatic switch less than a month ago from the new Vikings stadium with its 50,000 purple seats to the 17,000-seat Xcel Energy Center.

Longtime Minneapolis promoter Randy Levy took charge of the event in mid-September after efforts by out-of-towners fell through. “I was called in to see if maybe we could put Humpty Dumpty back together again,” said Levy. “It’s more work than I care to do, with so many moving parts. But, in the end, we’re able to fulfill this more as a tribute — Prince songs interpreted by great singers.”

Stevie Wonder, Chaka Khan, Christina Aguilera, Morris Day & the Time and Tori Kelly are among the big names in this all-star revue. Khan was excited Wednesday afternoon after rehearsing her four songs, including her Prince-penned smash “I Feel for You.”

“It’s like coming back to Mecca,” said the veteran R&B star, who has recorded with Prince at Paisley Park. “I saw his spirit all over this thing. It was a spiritually charged rehearsal for me. I didn’t expect it to be so beautiful and moving.”

While Mayer pulled out, several artists were added Tuesday including Mayte Garcia, the dancer who was Prince’s first wife, along with ex-Pussycat Doll Nicole Scherzinger and former Prince band members André Cymone and Michael Phillips.

This ever-evolving salute is how the unpredictable Prince rolled — flexible and spontaneous.

Or as Levy labeled it: “beautiful chaos.”

Thursday’s four-hour revue will be a step back from the $2.5 million production envisioned for U.S. Bank Stadium after Prince’s sister Tyka Nelson announced the official tribute concert in July.

Now Prince’s six surviving siblings, who have received no money from the estate thus far, are likely to share a six-figure proceed from the tribute at the X. The estate authorized use of Prince’s image and videos for the concert, but there will be no filming for a future broadcast or DVD. The just-opened Paisley Park museum is handling souvenir sales at the concert.

Prince booked for USBS

Before Prince died April 21 of an accidental painkiller overdose, his representatives had been negotiating to play the first concert at the Vikings stadium on Aug. 13.

Three days after he died, ex-Prince drummer Sheila E said she would spearhead the organization of a tribute concert to be held at the new downtown Minneapolis stadium.

“Sheila and I got involved to help set the direction for the family,” said Gilbert Davison, who was Prince’s manager in the 1990s and now manages Sheila E. “We wanted to let the family be in position to make decisions themselves. Then the estate took over.”

Bremer Trust, the bank affiliate which supervises Prince’s estate, enlisted L. Londell McMillan, a New York lawyer and publisher who had worked with Prince, and Charles Koppelman, a longtime music business executive, as official consultants to help the heirs exploit the assets of Prince’s estate, valued between $100 million and $300 million.

McMillan took charge but eventually couldn’t find a financial backer, having been turned down by Jobu Productions, a little known East Coast entertainment entity hoping to work with hedge funds, and Live Nation, the biggest concert promoters in the world. McMillan even asked U.S. Bank Stadium to promote the show.

“It was too risky,” said Michele Kelm-Helgen, chairwoman of Minnesota Sports Facilities Authority.

McMillan had contacted talent manager Irving Azoff, considered the most influential power broker in the music business, about enlisting some of his artists. And Azoff recommended Levy, who, for decades, had promoted the Eagles and other Azoff clients. After a week of conversations, Levy finally convinced McMillan to abandon his stadium ambitions.

“It’s difficult to put on a stadium show because of the massive amount of production,” Levy said. “It’s very, very, very expensive to do it at a stadium. The numbers get wacky to just open the stadium; it’s well into seven figures. And it’s not like it’s Metallica with a guaranteed wall-to-wall sell out.”

When McMillan agreed to a move to Xcel Energy Center, Levy signed on to finance and promote the concert. The event — announced a mere 28 days in advance — quickly sold out all 17,000 tickets.

At the insistence of Azoff’s staff, Levy approached the concert as if it were actually a Prince show. Hence, he hired industry leaders from around the country to handle sound, lights and video.

“It’s as if this is a major tour show but there is no tour,” Levy said. “It’s easily 150 people to put this on. We’re spending $120,000 on hotel rooms.”

Who’s in, who’s out

A key player is longtime Prince keyboardist Morris Hayes, who is serving as the show’s music director. He worked with all the acts to determine which Prince songs they would play. And he helped decide the batting order for the two-set program.

Since Oct. 3, Hayes has been rehearsing the house band featuring a revolving cast of former Prince sidemen in the New Power Generation including drummer Michael Bland and bassist Sonny Thompson. Out-of-town singers such as Khan and Judith Hill rehearsed with the NPG band Tuesday and Wednesday at the Myth nightclub in Maplewood. A run-through of the entire show will take place Thursday morning at the X.

Conspicuously absent from the lineup are Sheila E and the Revolution, Prince’s “Purple Rain” era band. Sheila had long ago booked a concert in suburban New York City for Oct. 13. Wendy Melvoin and Lisa Coleman of the Revolution made commitments before Prince died to work on music for the TV series “Shades of Blue” and “No Way Out.”

“We support the whole thing,” said Revolution drummer Bobby Z. “I’m coming.”

Some artists are being paid, some are just having their expenses covered, Levy said.

Mint Condition, the veteran Twin Cities R&B band known for its ’90s hits including “Breakin’ My Heart (Pretty Brown Eyes),” was the first act to commit even though things looked sketchy.

“It’s been a process,” said Mint Condition’s manager Jeff Taube. “It went through so many different transformations. The guys are committed to doing it.”

Mint Condition will open the concert with a medley of Prince tunes. Wonder will close the evening. And, like any Prince production, there will be lots of surprises.