NEW YORK: The main act of pop sensation Taylor Swift's wedding to NFL star Travis Kelce was due to get underway Friday, as celebrities flooded New York for the A-lister extravaganza at the storied Madison Square Garden.

The billionaire singer and three-time Kansas City Chiefs Super Bowl champion, both 36, opened the festivities Thursday with an exclusive rehearsal dinner for around 100 guests, according to US media.

Swift, who announced her engagement to Kelce last August, has been tight-lipped about what will surely be the wedding of the year, and guests have reportedly signed non-disclosure agreements.

But all signs point to the celebrations, which fall as Americans mark their country's 250th birthday, as being an over-the-top affair befitting one of the world's most famous and wealthiest couples.

An AFP journalist saw a procession of black SUVs, believed to be carrying guests, pulling into a privacy tent outside the Garden late Thursday while fans buzzed nearby for a peek.

"She is the biggest thing in America like she is our royalty, she is our queen, she is everything," said Alyssa Heinen, 24, from Manhattan.

"We are just so happy that she found the love of her life and he happens to also be such a big deal. It feels like a royal wedding to us."

Guests at Thursday's dinner included singer Selena Gomez, a close friend of Swift's who shared an Instagram photo of herself sitting in a car dressed in evening finery.

Singer Ed Sheeran, "Girls" creator Lena Dunham, producer Jack Antonoff and actors Bradley Cooper and Adam Sandler were photographed at or near the Garden, which was surrounded by barricades and police.

No phones

Friday's proceedings are expected to include around 1,000 guests, according to US media, including models Gigi Hadid and Cara Delevingne and actress Zoe Kravitz.

From the sports world, NFL players including George Kittle and Micah Parsons, former tight end Ross Travis, reporter Erin Andrews and her former NHL player husband Jarret Stoll reportedly have coveted invites.

Stevie Nicks and Tim McGraw will perform, while Ed Sheeran is also rumored to be among those taking the stage, according to New York Post gossip column Page Six.

Guests will reportedly not be allowed to have their phones during the event, which is expected to begin with mid-afternoon cocktails before a reception going into the night.

'So excited'

Swifties, as the megastar's fans are known, have flocked to Big Apple locations mentioned in their idol's lyrics.

Among the hotspots were Bus Stop Cafe in the West Village, which Swift has visited, and nearby Cornelia Street, which lends its name to the hit song.

"We are so excited to see Taylor," Lindsey Bongiorno, 25, told AFP outside Madison Square Garden, hoping to experience the occasion from afar.

Page Six reported that the couple had already tied the knot in front of "a tiny group of loved ones" ahead of their huge party, citing unidentified sources.

Journalists have sighted delivery trucks carrying lobster and doughnuts outside the arena.

Ahead of the big day, Swift's spokesperson said the couple were donating $26 million to various US charities, including in New York and Kansas City.

Madison Square Garden, which includes both an arena and a smaller theater, is perhaps not a traditional wedding venue but Swift would not be the first musician to marry there.

Sly Stone, who died last year, was married there in June 1974 to actress Kathy Silva during a concert by his band, Sly and the Family Stone.

Swift, a 14-time Grammy winner, is coming off a banner year with the success of her album "The Life of a Showgirl," induction into the Songwriters Hall of Fame and a new song on the "Toy Story 5" soundtrack.

Kelce, a tight end for the Chiefs, has signed on for a 14th season in the National Football League. He is also a co-host of the popular "New Heights" podcast alongside his brother Jason, which on Friday will host Britain's Prince William as its guest.

The royal was not expected to attend the wedding.

Madison Square Garden

Swift and Kelce set to tie the knot in glitzy arena extravaganza