Conversation so far:
What charitable causes was SMAP involved with?
SMAP have actively offered philanthropic support especially to the victims and regions affected by the 2011 Tohoku earthquake and tsunami and the 2016 Kumamoto earthquakes.
Did SMAP offer this support through donations or performing at a benefit?
SMAP hosted NTV's annual telethon, 24 Hour Television, and raised 1.1 billion yen. Kusanagi and Katori hosted the 24 Hour Television, again, and raised one billion yen.
What cause did SMAP raise the money for?
They bought a 30-second television commercial block in their weekly television program, SMAP×SMAP, to air a commercial on the information about the Japanese Red Cross Society.

Question: Was this their only time hosting a telethon?
Self-contained rewrite: Was this SMAP's only time hosting a telethon?