Red Velvet made their first appearance on a radio program through SBS's 'Kim Chang Ryul's Old School' on August 6 and discussed how they prepared for their debut and their first impression of other members.

Red Velvet said, "It has been one and a half years since the group was created with our current members. �We practiced for our debut song 'Happiness' for six months." They performed the song live for the first time since their debut on the show, receiving ardent applause. �

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MC Kim Chang Ryul said, "How was your first impression of one another?" �Joy said, "I was scared of Irene," making everyone laugh.

She continued, "Irene is severely shy around strangers, so she does not laugh easily. But now I really like her."