According to Mezamashi TV (2011.04.08), SMAP will sing the theme song for Katori Shingo's new drama, "Shiawase ni Narou yo"
SMAP's song is called "not alone ～幸せになろうよ～" or "not alone ~Shiawase ni narou yo~" OR "not alone ~let's become happy!" and it will be in limited release on April 25, 2011
Right now, SMAP & the cast of "Shiawase ni Narou yo" appear in special videos in a "YOU ARE NOT ALONE" message campaign. The videos in the campaign are of them saying "faito!" (Fight!) which are also in the youtube link above!
http://community.livejournal.com/smapxsmap/471279.html &
http://www.sanspo.com/geino/news/110...0507001-n1.htm