Girl group ITZY's Lia will be taking additional time off to look after her health, the singer said in a handwritten letter on Friday. She will not participate in the group's upcoming album or world tour.

Lia has been taking a break from group and solo activities since Sept. 18 due to health concerns.

“How are Midzy doing so far? I am doing fairly well, in my own ways,” Lia said in the letter uploaded to JYP Entertainment's fan communication website, JYPE Fans. Midzy is ITZY’s fandom name.

“After many thoughts and considerations, I have made the decision to not take part in the group’s upcoming album production and the world tour [and instead] focus more on recovering my health,” Lia said.

Lia released her solo track “Blossom” on YouTube the same day as a present for ITZY's fans. The song will be included in ITZY’s album that is slated for production in January, said JYP Entertainment, which represents Lia.

“For the fans who will miss me, I have unveiled my solo track ‘Blossom’ with its lyrics video,” she said. “It is a song that conveys my sincere thoughts for our fans [...] I will repay the support given by Midzy during the days I can’t be with you guys; I promise you to return healthy, with an even better form.”

“The company will take utmost care to support Lia’s recovery,” the agency said in a statement Friday.

ITZY completed its first world tour, “Checkmate,” in April and dropped its seventh EP, “Kill My Doubt,” in July. JYP Entertainment has yet to provide details about the girl group's upcoming album and world tour.

To find out more about ITZY, visit Celeb Confirmed!

BY CHO YONG-JUN [cho.yongjun1@joongang.co.kr]