The Empress of Soul added a little extra to the Super Bowl LIII national anthem on Sunday night, causing havoc in the wild world of offshore sports betting, where inside information is just part of the game.

On Friday afternoon, offshore bookmakers and bettors began hearing that Gladys Knight's rehearsal times for the national anthem were running longer than some expected. One offshore bookmaker received a text message from a confidant Friday: "3 rehearsals, none lip synced. 1:49, 1:50, 1:53."

Shortly after, bets started showing up at offshore sportsbooks throughout the Caribbean. Most of the bets were small in size -- $25 or $50 -- and the bulk of them were on the over on Knight's rendition of the anthem going over the 1-minute, 50-second betting line.

At 3:30 p.m. Friday, multiple $500 max bets on the over showed up at BetOnline.ag, an offshore sportsbook located in Panama.

"Once we saw the big bets come in, we figured there were rumors," BetOnline sportsbook manager Adam Burns told ESPN.

Around the same time, Costa Rican-based sportsbook MyBookie.ag also saw a surge of bets on the over.

"All of a sudden, people start betting in mass," David Strauss, director of wagering operations for MyBookie, told ESPN.

Betting on the length of the national anthem is not permitted at licensed sportsbooks in the U.S., including in New Jersey and Las Vegas, because bookmakers and regulators worry about inside information. In the offshore world, though, it's one of the most popular prop bets offered on the Super Bowl and has been for several years -- despite the potential for leaks.

"The steam [on the over] was caused by leaked info," Strauss added. "[Offshore] books don't pull it down because it's such an integral bet of the Super Bowl."

Gill Alexander, a broadcast host for the Vegas Stats and Information Network, said he received a text Saturday that said the music track Knight would be singing to was over or right at 2 minutes. The betting line and odds on the anthem were already moving significantly by then.

By Sunday, the over/under time at some books had increased by 8 seconds, from 1 minute, 48 seconds to 1 minute, 56 minutes. BetOnline, which opened the line at 1 minute, 50 seconds, chose not to adjust the time, but to instead increase the vigorish to bet the over. After opening at minus-120, bettors who wanted to back the over were now charged minus-300, meaning they were required to risk $300 for a potential $100 net win.

The alleged leak was only the first part of the controversy, though. On Sunday, while ending her performance, Knight repeated the last word of the final verse, "home of the brave," twice. The second "brave" stretched the song over 2 minutes by some counts. Some, but not all, sportsbooks graded over bets the winners. Other books, like BetOnline, had rules in place stipulating that the song is considered over after "the note 'brave' ends for the first time."

BetOnline oddsmakers ruled that Knight ended the first "brave" at 1 minute, 49.5 seconds, which would have made the under the winner. The company elected to pay both the over and under sides of the wager.

Hundreds of thousands of dollars are wagered offshore every year on the national anthem at the Super Bowl.