f(x)'s Sulli was revealed to show support for Amber's solo by visiting her at SBS's 'Inkigayo'.
She was spotted at SBS Open Hall by the fans who went to cheer on Amber's stage on February 15th. As she is taking a break from public activities, her appearance was sure a surprise to everyone especially f(x)'s fans.
Since the other members are currently busy with their overseas schedules, Sulli has become the first f(x) member to publicly support Amber's solo promotion.
Meanwhile, Amber is actively promoting 'Shake That Brass' on various music programs.