Conversation so far:
What was Jin Akanishi's first band?
After he was made a Johnny's Jr.
member in 2000.
Any notable songs with them?
CANNOTANSWER.
What happened next with Johnny's Jr?
CANNOTANSWER.
Was he with another band?
Akanishi was part of a number of groups like Musical Academy Dancing, J2000 and B.A.D..
Were they successful?
the sextet's unexpected popularity led their agency to allow them to expand into a separate group called KAT-TUN.

Question: When was KAT-TUN formed?
Self-contained rewrite: When was KAT-TUN formed?