The AAP has already announced its support to Kumar after a decision taken by its political affairs committee.
The AAP was not invited to the meetings of 18 opposition parties to finalise a candidate in the run up to the nominations.
The former Lok Sabha speaker, after being named as opposition's candidate for presidential election, had called on Kejriwal seeking AAP's support.
Kejriwal replied to the tweet, saying, "It was a pleasure to meet you Meira ji. Best wishes."
Kumar, the daughter of Dalit icon Jagjiwan Ram, is pitted against NDA's candidate Ram Nath Kovind, a former Bihar governor.
Four legislators are from the BJP-SAD combine, while one seat has been lying vacant since March after AAP legislator Ved Parkash quit party membership to join the BJP.
Voting is scheduled be held from from 10 am to 5 pm tomorrow.
Election commission officials said voting arrangements have been made at Delhi Assembly where a committee room has been converted into a polling booth.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)