SM Entertainment announced a surprise addition to Red Velvet prior to the rookie group's comeback.

Red Velvet, SM Entertainment's previously four-member girl group that debuted in 2014, will now have five members. SM Entertainment announced the news on March 11, revealing the new member, Yeri, to Red Velvet's fans. The company also announced an upcoming Red Velvet comeback, with the song "Ice Cream Cake."

Red Velvet's Yeri was introduced through a video on YouTube. The comments included a statement from SM Entertainment regarding Red Velvet and Yeri.

"With the new member, Red Velvet will widen the range or their musical potential and maximize the synergy effect among the members and present high quality performances.

The new member YERI (16) joined SMTOWN in year 2011 and performed during the August SMTOWN concery in Seoul. She's skilled in not only singing, but also rapping and dancing, leaving us to anticipate how she will contribute to the existing group."

SM Entertainment also shared images  Red Velvet's Yeri on social media. Yeri was a member of SM Entertainment's pre-debut group, SMRookies. The singer wrote a letter to fans on SMRookies official website.

"Hello I'm Yeri," she wrote. "I'm giving my surprise greetings from Red Velvet, are you all surprised? I'm practicing hard with the Red Velvet members every day! From now on I will show you a lot of my good traits so please give me lots of love and attention! I love you!"

Along with the message, the SMRookies website revealed information about Yeri's biography. She was born in March 1999, and specializes in dance and rap.

She is three years younger than Red Velvet's formerly youngest member, Joy.

Yeri was spotted by Korean outlet Newsen filming a music video with Red Velvet in the United States in February. At the time, there were rumors of an additional member being added to Red Velvet.

Red Velvet's website currently features teaser images of Yeri, as well as background music that is likely part of the audio for Red Velvet's upcoming song.

Red Velvet will make a comeback with "Ice Cream Cake" on March 18. The group will then perform at SMTOWN Live World Tour IV in Taipei on March 21.