Forte di Quattro (포르테 디 콰트로) is a South Korean male vocal quartet formed by the competition show Phantom Singer in 2017. The group debuted on May 18, 2017, with the eponymous album Forte di Quattro. History Background and formation Forte di Quattro, also known as FDQ, was formed during the first season of the competition show Phantom Singer and they were the winning quartet. The four members had separately auditioned for the show. They conceived the name to display their intentions of showing the "strength of four", as their name means in the Italian language. As the winning quartet, they won an exclusive contract to promote together for a year. Ko Hoon-jeong had studied voice at Kyung Hee University but chose to pursue a career in musical theater. Kim Hyun-soo and Son Tae-jin were already acquainted as undergraduate voice students at Seoul National University's famed College of Music. Lee Byeo-ri, then working in the theater industry, is the only member without any formal training in singing but had experience as an amateur singer with various vocal groups. 2017: Debut releases On May 18, Forte di Quattro released their debut album Forte di Quattro. They embarked on a nationwide tour, performing at seventeen different cities around the country. Following the success of the debut album, a repackaged edition was released in October. On November 21, they released their second full-length album Classica. This was followed by another nationwide tour from the album's release until the end of December. Compared to their debut album Classica was much more rooted in classical music and notably sampled melodies from the works of Rachmaninoff, Tchaikovsky and Bizet. 2018–present: Later releases and solo activities Each member resumed their respective solo activities under different agencies. Go returned to musical theater while Kim and Son became solo artists and have occasionally returned to performing classical repertoire with other fellow Phantom Singer contestants. In April 2018, the quartet performed overseas for the first time, making their debut in Japan. They performed at the Bunkamura in Tokyo, known as the home of the Tokyo Philharmonic Orchestra. The following month, they held a series of concerts in Seoul and Busan together with Phantom Singer 2 winners Forestella, whose members they were already acquainted with prior to Phantom Singer 2. To mark the occasion, they recorded and released a digital single, a remake of Renato Zero's hit "L'impossibile Vivere". Since 2019,