The 22-year-old was registered with the PSL today.
Hlongwane has become the second player to sign with Cosmos during the current transfer window period after Luyolo Nomandela finally joined from Mamelodi Sundowns.
Ezenkosi are also currently assessing Malawian midfielder John Banda with the view to signing him.
Cosmos boss Jomo Sono confirms the capture of Hlongwane.
“Yes, we have signed Hlongwane and Banda is training with us,” Sono tells KickOff.com. “We are free to assess any player [during this transfer window].”