
Chettha resigned his party leadership last month after refusing to vote the party line in endorsing the premiership of Abhisit Vejjajiva.
Pheu Thai Party leader Yongyuth Wichaidit called on Chettha at his home to deliver the party's invitation.
Chettha used to have an active role in the Thai Rak Thai Party before its disbandment in 2006.
Before the 2007 general election, he followed the splinter group to Ruam Jai Thai instead of teaming up with People Power Party, the reincarnation of Thai Rak Thai.
By yesterday's decision, he returned to his party's fold as Pheu Thai is the new banner of disbanded People Power.