f(x)'s member Krystal revealed a sibling-like chemistry with Super Junior's Ryeowook and SHINee's Jonghyun.

On Saturday, Ryeowook posted a picture on his Twitter before his concert in the waiting room.

The picture is with Krystal and Jonghyun, where the three are posing close to one another.

"First day in Osaka, going on stage soon! Wait for us~," said Ryeowook with the picture.

SM Town is holding a concert on Saturday and Sunday in Osaka, Japan.