Tamil Cinema as a lot of stars right now, and here is a list of films where the character's name was same as the star actor's name. While most of the contemporary stars have had such releases, Thala Ajith hasn't acted in a single movie where his name is Ajith. He came close in Vivegam, where his character name was AK. Scroll down to find the complete list:

Vijay in Nerukku Ner, Once More, Priyamanavale, Theri etc.,
VIJAY IN NERUKKU NER, ONCE MORE, PRIYAMANAVALE, THERI ETC.,