Thambidurai was present along with NDA leaders near the stage at the Ramlila Maidan here as Advani reached the venue to mark the end of his 40-day Jan Chetna Yatra.
The AIADMK is not a constituent of the BJP-led National Democratic Alliance (NDA).
But the AIADMK's gesture to support Advani's yatra comes ahead of the winter session of parliament beginning Tuesday.
It also signals growing warmth between Jayalalithaa and the BJP.
BJP sources told IANS that Advani was informed by the Tamil Nadu chief minister Saturday night that her party representative will be present at the final rally of Advani's anti-corruption journey.
Jayalalithaa had offered to back the Congress in parliament if the UPA parted ways with AIADMK rival DMK led by M. Karunanidhi.
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