"Mallika Sarabhai will be joining the AAP later in the day by going to their office in the city," they told PTI.
"She will be joining the party not as a politician but as a citizen of the country," they said.
In 2009, Sarabhai fought elections as an Independent candidate against BJP veteran L K Advani from the Gandhinagar constituency but had lost.
She has been constantly taking up the issue of oppressed and victims of the 2002 riots.
The AAP led by Arvind Kejriwal made a spectacular debut in the recent Delhi Assembly elections bagging 28 seats.