"Look who's coming to Lanford this Tuesday!" the ABC show's Twitter feed said Thursday.
A photo accompanying the message showed the couple sitting in The Lanford Lunchbox, the titular family's Illinois diner.
Whether they will play themselves or fictional characters wasn't specified.
The Conners co-star Sara Gilbert was a panelist on The Talk alongside Sharon Osbourne from 2010 to 2019.
The Conners -- a spin-off of the 1980s and '90s comedy Roseanne -- is now in its second season.