The renowned singer, who has officially started his mandatory military service, became the first Korean solo artist to achieve this notable milestone.Earlier in November, the Seven singer's debut album also surpassed Taylor Swift's 1989 (Taylor's Version) on the global sales chart.According to international media reports, the youngest member of BTS marked this achievement with massive 951,000 total equivalent sales of his album.Moreover, Jungkook’s single Seven from the album hit one billion streams on Spotify in October, breaking the previous record set by Miley Cyrus’ iconic song Flowers.Ahead of his military service, Jungkook penned a heartfelt note for his fans across the world, sharing that he will embark on a new journey this month."As I deliver this news, on one hand, my heart feels heavy but on the other hand, my heart warms up the precious memories with our ARMYs coming to my mind," he added.Jungkook concluded, saying, "I’ll miss you deeply while waiting for the day we meet again and share new stories."