Argentina's President Javier Milei performs hard rock anthem in front of 10,000 screaming fans (to promote his new book on neoclassical economic theory!)

A book presentation about neoclassical economic theory may not sound like a crowd-pleaser.

But on Wednesday in Buenos Aires mobs of star-struck fans packed a giant auditorium to hear Argentina's president, the libertarian economist Javier Milei, lecture on the importance of freeing capital from the control of the state. 

Greeted like a stadium rocker as he walked onstage to present his new book, 'Capitalism, Socialism and the Neoclassical Trap,' the libertarian president told the crowd: 'I wanted to do this because I really wanted to sing.'

Accompanied by a rock band, Milei grabbed a mic and swung into a cover of 'Panic Show' by Argentine hard rock band La Renga, whipping 10,000 fans into a frenzy.

'I am the lion,' he hollered, shaking his unruly hair to the beat. 'I am the king of a lost world'. 

President of Argentina Javier Milei sings during the presentation of his new book Capitalism, Socialism, and the Neoclassical Trap at Luna Park arena on Wednesday in Buenos Aires, Argentina.

The president sent fans into a frenzy as he performed his musical show

Milei is joined by a rock band as he belts out heavy metal song at book event

People wait in the Luna Park, where Milei (not seen) presented his book

When the music came to a stop, he tossed off his black leather jacket to reveal a business suit underneath and steps up to the podium to launch into the presentation of his new book, published May 1. 

Milei had initially planned to promote his book at the Buenos Aires International Book Fair, the country's largest literary event that kicked off earlier this month.  But when the left-leaning organizers gave speeches calling out Milei for defunding cultural institutions, the president canceled the event and promoted a new one at the city's Luna Park arena instead.

It wasn't Milei's first gig. 'Panic Show' performances with reworked lyrics were an occasional feature of campaign events. 

'This connection he has with people, I've never seen anything like it,' said 72-year-old attendee Liliana Varela as she watched Milei glad-handing supporters. 'He is creating a disruption at the very moment that we need it.'

Milei's musical stunt is not his first, with 'Panic Show' performances being a recurring feature during his campaign events

Milei's latest flamboyant episode Wednesday comes at a sensitive time for Argentina, in the midst of its worst economic crisis in two decades with more than half of the population living in poverty and annual inflation surging toward 300%.

An unprecedented diplomatic crisis is underway with Spain, Argentina's major trading partner, after Milei accused Spanish prime minister Pedro Sanchez's wife of corruption earlier this month, the Associated Press reported. 

Despite the turmoil Milei's ratings have stayed strong, with die-hard fans out in full force on Wednesday, lining up for hours in frigid weather and dancing to keep the energy up when Milei ran over an hour late.

'He's the best president in the world,' gushed 20-year-old Matías Muzica, dodging questions about his policies but praising him as Argentina's answer to Donald Trump. 'He can make Argentina great again.'