"H D Kumaraswamy will file his nomination at Chikkaballapur tomorrow," said a JD(S) statement.
Kumaraswamy is aiming at gaining hold in a new turf, where Vokkaligas, to which he belongs, are a dominant community.
The former chief minister quit as MP of Bangalore Rural after winning from Ramanagaram in the assembly polls. In the bypoll, his wife Anita Kumaraswamy lost to Congress's D K Suresh.
AAP, which had listed both Moily and Kumaraswamy in Arvind Kejriwal's list of "most corrupt" politicians, has fielded a retired CRPF DIG Arkesh for the seat.