The change of heart by Jayalalithaa to accommodate CPI came after Raja called on her this morning and sought support.
Chief Minister and AIADMK supremo J Jayalalithaa in a statement released to the press here announced that her party would extend support to the candidature of Raja.
AIADMK'S Thangamuthu, who was fielded as fifth candidate would withdraw his nomination, she said.
Earlier, Jayalalithaa had expressed her party's inability to help CPI and nominated five of her party candidates for the election.
DMK has entered the poll fray by fielding party supremo M Karunanidhi daughter Kanimozhi, who is bidding for a second term.
AIADMK with 150 members strength in the 234-member state Assembly is expected to win four seats. Each winning candidate has to muster 34 first preference votes for victory.