Charlie Siem is making classical music sexy again. He started playing with the Royal Philharmonic Orchestra, in London, at age 18. Later, he appeared in Armani, Dior, and Dunhill campaigns. Now 36, he’s a virtuoso violinist who has made his instrument popular among the likes of Katy Perry and Lady Gaga. (He serenaded Gaga at her C.F.D.A. Fashion Awards after-party.)

Siem wasn’t born into a long line of musicians. (Though he is related to Ole Bull, the prodigious 19th-century Norwegian violinist and composer.) Nor did overbearing parents hand him the violin at a young age. Instead, they played classical music for him and his two sisters to “develop [the] young children’s brains.”

But as a toddler in London, the melodic notes of Beethoven’s violin concerto captured his attention. “I was very small. I was about three or four years old, and I heard the violin on the radio,” he says from his home in Florence. Music therapy came next, and then lessons. By seven, Siem was practicing two hours a day under the watchful eye of a teacher from the Guildhall School of Music and Drama.

His dedication made his parents, who wanted him to hang out with other children on the playground, uneasy. “They weren’t sure it was necessarily the healthiest thing for their child to be completely focused only on one thing,” he says, “especially something like playing the violin, which isn’t something they thought I’d develop into a career.”

Commercial success came into view for Siem when he was 15, a time when his classmates at Eton were having their first tequila shots. In 2001, he was signed by the modeling agency IMG Artists and had one of his first major concerts, in Rio. He doesn’t remember being nervous about the performance. “I didn’t have much over-excitement or paralyzing adrenaline or anything,” he says. “I sort of just walked on and did it.”

By seven, Siem was practicing two hours a day under the watchful eye of a teacher from the Guildhall School of Music and Drama.

After playing in Vilnius and in Bergen, he went on to pursue a music degree at the University of Cambridge. Post-graduation, he studied under Shlomo Mintz, the master Israeli violinist.

The “fashion thing” started later. In 2010, Mario Testino saw a video of Siem wearing a tank top, playing alongside the Royal Ballet in Havana. “[Mario] got in touch and said, ‘Listen, I’d love to meet you.’” A year after that, Siem was playing a Paganini caprice at the launch of Testino’s Kate Moss book at an art gallery in London. He sees his modeling work as a way to bring classical music to a younger generation. “I think it’s an obligation of a young artist to do what you can to get it out to a wider audience.”

Despite Siem’s Bella Vita on Instagram, where he posts from the steps of cathedrals in Florence and from boats in the Greek islands, practice with his 1735 Guarneri del Gesù violin (known as D’Egville) is rigorous—an uncompromising two hours a day. “The violin, in particular, compared to all other instruments … it’s kind of merciless,” he says. “It’s a fine balance between getting every technical element right, but also sounding natural, like you have soul in there.”

Next month, Siem is releasing Beethoven: Violin Concerto, Romances, on which he plays the Violin Concerto in D Major, Op. 61—Beethoven’s only violin concerto, and one of the most difficult violin pieces to learn. “It’s been a kind of soundtrack to my life,” he says. “I always avoided playing it because I always thought this piece is so, so challenging, and one has to be such a profound and great musician.”

Learning the score, like practicing or preparing for a performance, requires high levels of concentration. “It’s very much part of my daily discipline,” he says. “But this is art too.”

Charlie Siem’s Beethoven: Violin Concerto, Romances will be released on August 5

Elena Clavarino is an Associate Editor for AIR MAIL