Kordell Stewart -- Playdate w/ Baby Mama Tania Richardson Hours Before Divorce

Before publishing ... we contacted Kordell's rep, who told us the woman in the photo was Kordell's baby mama, Tania Richardson.

Tania contacted us Friday, and said she is not the woman in the pic.

Calls back to Kordell's people have not been returned.

The night before Kordell Stewart filed for divorce from his wife Porsha Williams, he was hanging out with another woman -- his baby mama -- and TMZ has the pic.

Kordell -- a former NFL star who spent years with the Pittsburgh Steelers -- spent Thursday March 21 at Dave & Busters video game arcade restaurant in Marietta, Georgia with former flame Tania Richardson and their son Syre.

Sources close to Kordell tell TMZ ... Stewart was initially booked to appear at the restaurant as part of an event for a local radio station where he works ... but thought Syre would enjoy the place, so he called up Tania and invited them over.

It's unclear if Kordell and Tania talked about the NFL player's marriage ... but witnesses inside the joint tell us the two appeared to be having a serious conversation and Kordell looked stressed out.

We broke the story ... Kordell filed for divorce the very next day -- and Williams (who stars on "Real Housewives of Atlanta") claims she was blindsided by Stewart's actions.