Netizens were shocked to learn that the child actor playing the role of Kim Tae Hee's daughter in her comeback drama Hi, Bye, Mama! was a boy.

The news drew mixed reactions from netizens who were perplexed by the production's decision to cast a female role to a male child actor when there are plenty of female child actresses who can also play the role.

According to a report by KstarLive, interest grew about the child actor who played Kim Tae Hee's daughter as soon as the first trailer of the drama was released. They quickly researched Seo Woo Jin but were shocked to find out that he was a boy.

The five-year-old actor previously starred in many dramas including VIP, Love with Flaws, The Light in Your Eyes, Save Me, Kangnam Style and Go Back Couple.

Seo Woojin reportedly earned high praise from the Hi, Bye Mama! production team for his first time to portray a female role because he did it perfectly without being awkward.

Meanwhile, according to a source from the production team, there was a simple reason Woojin was cast as Kim Tae Hee's daughter."We cast him because he looks identical to Kim Tae Hee and because of his stable acting skills," the source explained.

Many members of the production were reportedly surprised that Woojin was a boy when they found out about it.Hi, Bye Mama! is Kim Tae Hee's first acting project after giving birth to two daughters and her marriage to pop superstar Rain.

She also takes on a mother role for the tVn drama which revolves around a woman who dies in a tragic accident but is given a chance to return to her husband and daughter for 49 days as a ghost. Seo Woojin plays the role of the daughter while actor Lee Kyu Hyung plays Kim Tae Hee's husband.

The first episodes of Hi, Bye Mama! started airing on tvN last February 22. The drama fills the timeslot previously occupied by the smash hit Crash Landing on You, which finished with the highest finale ratings for tVn, overtaking the three-year record held by Goblin.It seems that Kim Tae Hee was also anticipated by her fans because the premiere ranked No. 1 for its timeslot with 5.9 percent nationwide. It peaked at 7 percent for the premiere episode, Soompi reported. Hi, Bye Mama! topped the timeslot for cable and non-cable shows.