Messi Mania has grabbed hold in Major League Soccer, but will it be a long-lasting boost?

It's highly unlikely any player other than Lionel Messi could have brought Prince Harry, Selena Gomez and Leonardo DiCaprio out to a regular-season Major League Soccer match.

But there they were -- very noticeable in fact -- in the crowd when Messi's Inter Miami squad took on LAFC in Southern California early this month.

Since Messi arrived in the United States, the league and his team have both been enjoying a rare spotlight, with sells-outs on the road and at home, No. 10 jerseys flying off the shelves, ticket prices at times reaching unheard-of levels and sponsors jumping on board.

"He's the best player in the world. What did you think he was going to do when he came here?" LAFC coach Steve Cherundolo said after Inter Miami's star-studded sold-out match in Los Angeles.

It's almost necessary to be an A-lister to score a good ticket to watch him play: Front-row tickets on the secondary market have been going for thousands of dollars. Regardless of the costs they may incur, more fans are going through the turnstiles to watch the seven-time Ballon d'Or winner and reigning World Cup champion.

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"I was never an MLS person," said Kenny Schorr, a fan from Miami Springs and former college soccer player who was at a recent Inter Miami game. "I would watch a game and get frustrated. The talent level was so different. I'm not trying to put anybody down, But you look at what Messi does and the talent is only going to increase with his presence."

Messi Mania has even reached beyond the pitch.

The day after Messi posted on social media about his meal from Banchero Pizza, a homey Argentine-style pizzeria in Miami's North Beach, there was a line out the door at the restaurant.

Clearly, the demand for all things Messi is off the charts, but will that translate to greater success for MLS in the United States, where "football" means the NFL not soccer?

"With the arrival of Messi, everything is changing, everything is opening eyes," LAFC defender Giorgio Chiellini said. "It's a step. Part of that has to be a step, then many will want to invest and they could have the opportunity to do it. This league has huge potential. Now it's time to show this potential."

Messi, 36, has 11 goals and eight assists in 12 games across all competitions for Inter Miami. He's already helped the team secure one trophy, this summer's League's Cup. On Wednesday, Miami will host the Houston Dynamo for another title, the U.S. Open Cup.

But Messi's status for the game is uncertain: He's been dealing with scar tissue from an old injury, according to coach Tata Martino. Even so, tickets on the secondary market for Wednesday's match were ranging from about $170 to more than $5,000 apiece.

MLS has gotten a bump from an international star before. David Beckham, now Messi's boss as co-owner of Inter Miami, was a game-changer for the league when he signed with the LA Galaxy in 2007. The league literally changed the rules for Beckham, devising the Designated Player rule that allows teams to sign high-profile players without them counting toward the salary cap. Messi was signed under the same rule.

With his Hollywood good looks and his Spice Girl wife, Beckham raised the profile of the league.

Fox Soccer analyst Alexi Lalas, who was president of the Galaxy when Beckham joined, said that while Beckham helped boost the league's profile, Messi is elevating the game itself.

"Messi is arguably the greatest player to play the game. That conversation was not had relative to David Beckham, as good as he was as a player," Lalas said. "I think the impact of Messi is going to be greater in terms of the on-field product and the evolution and the growth of that, in that I think that he almost gives license to others to at least consider coming to Major League Soccer."

For now, the fans are responding to what MLS is offering with Messi as the face of the league.

So far, average attendance in MLS is up nearly 5% over last year, although the league also added a new team in St. Louis this season. Inter Miami's attendance is up 36% over last year.

Television viewership is more difficult to gauge because league games are broadcast on Apple TV's MLS Season Pass, a subscription-based streaming platform that was launched this season. Apple TV hasn't shared ratings.

Streaming measurement firm Antenna reported 110,075 new MLS Season Pass signups on the day of Messi's Inter Miami debut. That's a 280% increase from the number of sign-ups on opening day of the 2023 season. Another 65,000 signed up when he played his second game, according to data first reported by the Wall Street Journal.

Messi's No. 10 jersey is the best-selling jersey in the history of the MLS store. Sales surpassed every other jersey sold this season on the league's website within just 45 minutes of its release, and there's a backlog of orders still waiting to be filled.

Sponsors are also buying in. Royal Caribbean signed a multiyear partnership deal with Inter Miami in August.

All told, Inter Miami chief business officer Xavier Asensi has predicted in interviews that the club is on target to hit record revenues of more than $200 million in 2024, on par with some European clubs.

Still, it remains to be seen how widespread the Messi effect will be, whether fans will be wooed to the league as a whole.

Julio Morales, who was holding a painting he did of Messi before the Miami match at LAFC, said he paid $600 for his ticket to see Messi.

"We'll see how the games go," Morales said about whether he'll start following MLS. "I mean, if the games get better, then maybe."