What “The Big Bang Theory” star Jim Parsons thinks about Michael Keaton as Sheldon Cooper

“The Big Bang Theory” was never a critics' darling, and critics were a little baffled when they found that “Young Sheldon” was starting to win them over. But both shows were huge Nielsen ratings hits that attracted plenty of big-name guest stars. The former earned its nerd reputation with appearances by “Star Trek” legends like Leonard Nimoy and LeVar Burton, while it achieved TV immortality by casting sitcom god Bob Newhart as Professor Proton. As for “Young Sheldon,” producers welcomed Newhart to TV as a science host and also brought in big-name talent like Melanie Lynskey, Jason Alexander and Lance Reddick.

No matter what you think of these ultra-mainstream shows, you have to accept that there is no shame in making a cameo in the universe of The Big Bang Theory.

Now we know that CBS will be going deeper into this geek territory…