BIG STAR leader FeelDog recently celebrated the group's 100th day since debut with a special handwritten letter to fans.

On October 19th, the group's official Twitter was updated with a photo of his handwritten letter titled, 'To. Our ONLY ONE'.

In the letter, FeelDog expressed his gratitude towards fans, stating, "Four years of practice, and our debut, first stage. I can't believe it has already been 100 days since we've been together with our 'ONLY ONE', who have been with us since July 12th. Although we still lack as a rookie, we were able to confidently stand tall thanks to 'ONLY ONE'. Although this comment is cliche, I hope to be with you guys for 100, 1000, 10000 days. Thank you for staying by our side."

Along with the letter were short messages written off to the side. One read, "I want to treat you all to a meal. Seriously, should we go to a BBQ restaurant?" and drew a caricature of himself below the message.

In addition, the other members of BIG STAR also left their own handwritten messages on the group's official fan caf� titled, 'BIG STAR's 100th day since debut! A message for our ONLY ONE'. You can check them out on the fan cafe page here.

Meanwhile, BIG STAR is currently actively promoting their latest title track "Think" off of their first mini album 'Blossom'.