Aspiring musician jumps from audience to save ailing concert performance suddenly.

During a "La La Land" score performance, a musician's sudden illness prompted composer Justin Hurwitz to seek a sight reader on short notice, and a 21-year-old student responded promptly.

Sterling Nasa, a 21-year-old aspiring musician, began his day like any other on that fateful Saturday morning.

That ordinary day began with assisting a friend on a student project and running personal chores around town. In the evening, he had tickets to see "La La Land" accompanied by live orchestra at the Darling Harbour Theatre within the Sydney Convention Centre in Australia.

The ordinary day transformed into an extraordinary experience by nightfall suddenly.

His online fame has caught him off guard, and he's still trying to wrap his head around it all.

During an intermission in "La La Land," a pivotal 2016 musical, chaos erupted after the first half's conclusion. The drama revolves around Mia, an aspiring actress played by Emma Stone, and her encounter with Sebastian, a driven musician portrayed by Ryan Gosling.

As the interval dragged an unsettling feeling began to spread through the audience, with many wondering what was causing the delay. Suddenly, composer Justin Hurwitz appeared on stage.

Mr. Hurwitz scanned the audience for a skilled musician, specifically asking if anyone was an exceptional sight reader. A sudden absence had left a crucial gap, as one performer had been forced to leave due to illness and couldn't return.

Facing the daunting task of performing with a professional orchestra unprepared, Mr. Nasa found himself navigating unfamiliar territory, turning each page to confront a fresh set of obstacles in this high-pressure situation.

A frantic cry echoed through the venue, akin to "is there a medical professional present?" Mr. Nasa replied.

Scarlett Pearce sprang into action as she raised her hand in response to Mr. Hurwitz's call for volunteers by his side.

In a candid phone conversation, she described herself as a bit unhinged, revealing her bold decision to address the 2,000-strong audience directly, urging them to rally behind Mr. Nasa.

Ms. Pearce recalled her friend's hesitant gesture, prompting her to discreetly guide his hand upwards for a show of support.

Ms. Pearce recalled feeling uncertain about her initial interaction with him, but confidently predicted a turnaround within 10 minutes.

Mr. Nasa's enthusiasm was sparked by the crowd's cheers as he stood up from his seat and made his way towards the stage, where a performance was in need of revitalization.

Mr. Nasa recalled his desperate attempt to avoid tumbling downstairs.

As soon as he reached the stage, Mr. Hurwitz requested the musician's name and then passed him over to the keyboard technician for a concise briefing.

The moment of truth arrived promptly at that time.

Mr. Nasa's initial jitters quickly dissipated as he settled into the concert, but a crucial turning point came around 10 minutes in when he suddenly clicked with his music. He then shifted focus from anxiety to fully embracing the experience. "You only get so many chances like this," Mr. Nasa reflected.

During "Start a Fire," a crowd-pleasing tune from the movie, John Legend's rendition was showcased. Meanwhile, Mr. Nasa seized an opportunity to improvise on the keyboard, earning thunderous applause from the enthusiastic audience.

A sudden leap into the spotlight befell Mr. Nasa just as he was nearing graduation from the University of Sydney's international relations program.

Music is where his true enthusiasm lies. Mr. Nasa credited the spontaneous stage time with instilling in him the courage to contemplate music as a professional path. Performing alongside seasoned artists, he noted, made his aspirations seem less far-fetched.