BTS member Jin is feeling grateful for the group's fans on his 26th birthday.

The South Korean singer penned a sweet, handwritten letter to the boy band's fans, known as Army, on his birthday Tuesday.

"I'm happy not only because it's my birthday but mainly because Army members are happy celebrating my birthday together," he wrote, according to The Korea Herald.

Jin thanked Army for its support of BTS, which won the daesang, or grand prize, and four other awards at the 2018 Asia Artist Awards last week.

"I'm so happy with the 'Daesang' but I'm so so happy about the 'Popularity Award' that resulted from the hard work of our Army. Thank you so so much Army!" the K-pop star said, according to allkpop.

"Sorry to my international Army that I am not good at English. But I love you," he added in English.

BTS released the album Love Yourself: Answer in August and will next perform Saturday in Taoyuan, Taiwan, on its Love Yourself world tour. The group released a music video with Steve Aoki for the new song "Waste It On Me" in November.

The Korea Herald reported Tuesday that BTS' agency, Big Hit Entertainment, has trademarked "BTS" and "Army" in light of the group's success. The company previously trademarked "Bangtansonyeondan," the group's Korean name, and "Bangtan Boys."