Inside Britney Spears' Return to Las Vegas for Fiancé Sam Asghari's Birthday

This is the first time the pop star has been to Vegas since her conservatorship ended.

Britney Spears returned to Las Vegas for the first time since ending her long-running residency and getting out of her conservatorship. The 40-year-old pop star was in Sin City over the weekend to celebrate her fiancé, Sam Asghari's, 28th birthday.

While there, Asghari took in the UFC 272 fight and the soon-to-be married couple enjoyed private dinners and some time at the spa.

Ariadna Jacob, founder of Outliers Talent, set up the couple's trip to Las Vegas, and tells ET that she "worked with several clients to curate what would be an unbelievable experience" for Spears and Asghari, starting with providing the couple with jet transportation.

"Sam and Britney had a nice, luxurious, and romantic weekend together while celebrating Sam's birthday," a source tells ET. "They stayed at the presidential suite at Resorts World, overlooking Vegas."

The couple enjoyed in-room massages in their palatial two-bedroom presidential suite, which was complete with floor-to-ceiling windows, featured views of the Strip, a private gym space, living space, dining room, entertainment room, and all of their favorite snacks.

Spears even received an in-room manicure from Miss Behave Beauty Bar, and Bali Basics Las Vegas created a stunning rose petal flower bath with the initials SB in the suite’s soaking tub.

Meanwhile, ET's source says that "Sam woke up early to workout at the fitness center during the trip and loved meeting Chuck Liddell since he is a UFC fan."

Jacob, who helped plan the couple's trip, added that Asghari attended the UFC fight with Kevin Ostaj, a photographer and filmmaker and action sports star Johnni DiJulius.

Jacob tells ET that she was tasked with arranging the getaway after reaching out to Asghari's manager to gauge his interest in coming to Sin City.

"Sam had expressed interest in checking out a UFC fight, so I called my good friend, Chuck Liddell, to see if he could host him personally," Jacob says. "There’s nothing like an invite to UFC from the legend himself, so I knew that would make Sam's first UFC fight memorable."

Other "small touches" the company provided included a private dinner at Wally’s Wine & Spirits, where Spears and Asghari were treated to live entertainment by pianist Otto Ehling and singer Katie Welch

Ehling shares with ET how he came to give the couple a private performance.

"I got a last-minute call from Katie Welch, the singer who I performed with for Britney and Sam, about this gig. We played together a couple weeks ago and jived well. Katie is based out of Los Angeles and called me the day before saying she is coming to Vegas and that we have to do this gig together. She came to Vegas straight from L.A., and we rehearsed for two hours," he says. "We picked out a set list of songs that we thought Britney could relate to, while also giving her a taste of Vegas. We played everything from Frank Sinatra's 'Fly Me to the Moon,' to the Backstreet Boys' 'I Want It That Way' in a jazzy style that was tons of fun."

Ehling says the couple enjoyed the night, noting that they even got up a few times to dance to the music.

"Their dinner table was set up in front of a little stage in a beautiful private room at Wally's at Resorts World," he adds. "Britney and Sam looked so happy the whole time and they were chatting and enjoying the music. It was an honor to provide entertainment for them."

Welch, who has been a lifelong Spears fan, tells ET is was "such an incredible and honestly surreal experience."

"I’ve been a huge Britney fan since I was a little girl, I've seen her in concert so many times, so to be the one singing for her while she laughed and danced and enjoyed herself, was beyond my wildest dreams," Welch gushes. "They were wonderfully sweet and supportive, and they really seemed to be enjoying the evening. They just looked so in love and so happy together. I feel incredibly honored and grateful for the opportunity to have been a part of their experience." 

Jacob's company also "provided a professional stylist, an incredible cake, a flower designed bath tub and some other intentional details to create a fresh start in Vegas for the couple in love."

In a since-deleted post, Spears touched on her time in Vegas and shared what it was like to be there for the first time since her residency. Spears said she was treated like an equal in Las Vegas for the first time in 13 years and was able to enjoy Vegas not as a performer, but as a guest, who was able to get wined, dined and pampered, in a city that many flock to for just that. While doing her residency in Vegas from 2013 to 2017, Spears was still under a conservatorship controlled by her father, Jamie.

"Since Britney decided to join privately as Sam’s personal guest, I wanted Britney to know she is loved and deserves to be treated like a queen," Jacob says. "I have so much personal admiration for what she went through. Britney deserves respect, privacy, love and compassion from all of us."

ET's source adds that "it was a fresh start for Britney to be back in Vegas in a new way with Sam by her side as her fiancé."

"Everyone involved in her trip there was extremely respectful of her and her privacy, and that meant a lot to her," the source says. "Sam and Britney are so supportive of each other, and Britney is incredibly proud of Sam and everything that he is doing. They are both so motivated."

Jacob notes that Asghari "surrounds himself with wonderful people and it’s unmistakable the genuine love, admiration and protection he provides the people he cares about."

"Sam is independently talented, creative and a rising actor not to be underestimated," she adds. "His personal brand is about motivation, style, fashion, fitness, and a luxury lifestyle so many brands align with what he stands for. I’m really happy for them both."

The couple has been celebrating Asghari's birthday since the start of this month. See the video below for more on how Spears helped her fiancé ring in his 28th year.