The Big Bang Theory's Johnny Galecki says 12th season may be the last

Blast from the past, early scene of The Big Bang Theory. Photo / Getty Images

The Big Bang Theory could be over after next season.

Johnny Galecki revealed on Saturday that the wildly-successful CBS program could wrap up when the show's 12th season concludes after the 2018/2019 TV season, reports The Daily Mail.

The 42-year-old actor made the remarks while appearing on a panel at the Television Critics Association winter press tour in Pasadena, California, as he was asked about the future of the program, TV Line reported.

"The only manner in which the cast has discussed wrapping the show is that we're all going to be very sad when that day comes," said Galecki, who plays Leonard Hofstadter on the top-rated sitcom.

"But I think at this point, everyone's very comfortable with 12 seasons being the time to go home and see our families."

The long-running Chuck Lorre comedy, which also stars Kaley Cuoco, Jim Parsons and Mayim Bialik, has also spawned the successful spin-off Young Sheldon.

Galecki also addressed his one-off stint on ABC's Roseanne reboot, revealing that due to his prior commitments - and the fact that it airs on a rival network - he's limited to one show to reprise his role of David Healy on the reboot.

"There were just some politics to be considerate about," the CBS star said of his appearance on the ABC sitcom, noting that it was a tad awkward to do so, but he remembered his roots.

"It was probably most unconformable only to me because obviously Big Bang is my home and my family. But I probably wouldn't have been on Big Bang if it hadn't been for Roseanne," Galecki said.

The veteran actor didn't rule out the option of returning to the show in future seasons, as he said that if the Roseanne reboot returns "next year to do another eight or nine [shows, he] would love to do more than one."

Galecki appeared on the panel to promote Living Biblically, a CBS show he's executive producer on.