While the actor currently stars on TheBig Bang Theory, he was able to return to Roseanne for one episode, and started rehearsals on Tuesday.
"We have got our Johnny Galecki back on Roseanne this episode - what a joy to work with such a deeply empathetic actor,” Roseanne Barr tweeted on Tuesday. “Very moving 4 all of us. #JOY.”
Galecki's onscreen wife, Sara Gilbert (who plays Darlene to his David Healy), told ET in September that the show was trying to get him on board.
"We're in very productive, amazing talks and we're hopeful that it will work out," she shared.
See more in the video below.