Girls Generation's Taeyeon is once again blessing everyone with a soulful ballad song.

On Thursday, Taeyeon dropped the music video for her new song "Nights into days."

The single was written and produced by Soul Yoo Naul, a South Korean singer and member of the Brown Eyed Soul.

The "Nights into days" is part of Naul's 'Ballad Pop City' project.

In a message to her fans, Taeyeon said she likes Nail and has been a fan of him for a long time.

"I'm so happy to be able to work with him like this. Guess that I'm a successful fan," she said.

Taeyeon shared that the songs of Brown Eyed Soul became her "only small-but-certain happiness" during her schedules with Girls Generation,

"The day before yesterday, when I took a walk with Zero, I kept replaying 'Nights into days,' and it's really warming," Taeyeon said.

"I felt so happy listening to both Naul-nim's version and my versions of the song," she added. 

Taeyeon debuted in the nine-piece group Girls Generation in 2007. 

She embarked on a solo career in 2017 with her first mini-studio album "My Voice."

The 33-year-old singer is known for her outstanding vocals.

Watch the full music video here: