More details about Britney's Vegas show + questions about GMA sickness & lipsyncing claims answered.

Since pop-princess superstar Britney Spears announced her new two-year residency at Planet Hollywood starting Dec. 27, we’ve learned a lot of behind-the-scenes “Piece of Me” concert secrets.

The multimillion bet on Britney has already started to pay off for Caesars Entertainment, which owns and operates Planet Hollywood. Her announcement last week in the desert just outside Las Vegas grabbed headline stories and radio and TV coverage all around the world.

It prompted a virtual flood of ticket sales and hotel-room bookings. I asked Tariq Shaukat, chief marketing officer for Caesars Entertainment, for reaction from just the first 24 hours. He told me: “We’re very pleased, and, as we suspected, interest in Britney is very high from all over.” Three of her first shows apparently sold out within the first hour, and sales for the first group of 16 shows through February are still going strong five months out.

Another Caesars executive, Kurt Melien, VP of entertainment, said: “It will be a big Las Vegas-style production show married to a dance-club environment. It’s a 90- to 100-minute show with 21 of her greatest, hits and some of the new music from her eighth studio album being released Dec. 3. It’s a retrospective on some of the most iconic moments of her life combined with the contemporary material she’s doing today.”

Britney herself promised Ryan Seacrest on his radio show: “We are going to have all the works — snow, water, rain, everything. Every time I do a show, I like to really bring it. I love to put on a show that will really entertain fans. We want the feeling that fans will be in the show with me. We’re going to have a cool set-up for them with a party vibe so they are really there with me.”

Planet Hollywood President David Hoenemeyer said, “We have the world’s largest indoor-projection theater, so it will be an explosive theatrical experience where the audience can dance the night away as they relive their favorite Britney moments.”

The theater will have private VIP tables, banquettes at the dance floor with VIP champagne bottle service and a high-rollers’ entrance with walk-in escort. There are four $1,000 VIP per-person packages, including a meet-and-greet with Britney, plus, souvenir photo for $2,500.

Let’s set the record straight on some of the rumors that have run rampant since Britney’s 5:30 a.m. desert appearance at the Jean Dry Lake Bed with “Good Morning America’s” Sam Champion on ABC last Tuesday.

* She beat back effects of motion sickness while her helicopter hovered above the landing site during its 50-minute total flight time, but she did not throw up.

* She kept her sunglasses on for the pre-dawn interview because her eyes were teary from feeling sick.

* She did confirm that concertgoers might occasionally see 7-year-old son Sean Preston onstage with her, but doubted that 6-year-old Jayden would join her during the performances.

* She will move here as of mid-November to start the in-theater load-in and rehearsals for the Dec. 27 premiere.

* She will perform new songs about the self-confessed breakup after four years from then-fiance Jason Trawick, a Hollywood agent. “It’s a therapeutic way to get over it, but breakups do suck,” she said.

* She will definitely be singing and dancing — no lip synching, as incorrectly reported elsewhere. Britney has been working five hours daily with one of Hollywood’s strongest keep-fit trainers and a vocal coach all summer.

Sam told me: “She sounds and looks in the best condition of her entire life.” Kurt added: “She’s in the physical shape and vocal shape to sing the entire show.” Most important is that Britney is “super pumped and really excited about the show and has already been working out and rehearsing ever since negotiations began.”

* The Planet Hollywood residency at PH Live is a two-year exclusive. Britney will not be seen in concert anywhere else in America during the nearly 100 weekend concerts. The dates are staggered — one mid-week and two or three on weekends depending on holiday periods so it gives her time to rest her throat and vocal chords in our dry, high-desert climate.

Some of my Twitter followers misread my earlier stories: She will have available time to go to Europe and South America for appearances if the opportunities arise, but not for a world tour.

* Baz Halpin, who has worked on tours for Katy Perry, Pink, Lady Antebellum and Taylor Swift, is directing “Piece of Me.”

Insiders say that in addition to Britney’s mega-bucks paycheck over the two years, Caesars ordered a nearly $20 million renovation for PH Live after buying out the lease from producers Base Entertainment for $15 million. It had been used little in the past year, for the Miss America, Miss USA and Miss Universe pageants and a few concerts.

It now becomes the Strip's first theatrical dance-club experience. The seating has been trimmed from a sprawling 7,500 to a more-intimate 4,500, with two areas for dancing by table-service seating at the edge-of-the-runway stage shaped like an inverted anchor. Almost all the walls will be used for projections. Officials describe the effect as similar to being inside a planetarium.

Britney looked like a glamorous superstar when she returned to Las Vegas to introduce Miley Cyrus at the 2013 iHeartRadio Music Festival at MGM Grand Garden Arena on Saturday night. She wore short black shorts, a black-choker necklace and a cropped tuxedo top displaying a sparkling-diamond, black lacy bra.

She summed it all up: “I’m very ready for this. I’m ready physically, mentally — definitely. I love Las Vegas, and the energy is really, really good. The show will be completely different from what everybody might be expecting. It’s the best project I’ve ever tackled. It couldn’t be more exciting.”

I bolded the main points but:

tl;dr, She didn't throw up. Put sunglasses on because her eyes were watery from feeling sick. She's been training 5 hours a day dancing with a vocal coach. She will be "singing." She will be moving to Vegas in mid November for full on rehearsals in the venue until opening night. There will be video projections on every wall of the venue during the show. And shows are selling well contrary to reports.