FOX NEWS: 'Big Bang Theory' actor Johnny Galecki says guest star Mark Hamill is obsessed with 'Roseanne' trivia

'Big Bang Theory' actor Johnny Galecki says guest star Mark Hamill is obsessed with 'Roseanne' trivia



“Big Bang Theory” finally landed one of nerd-culture’s biggest guest stars for its Season 11 finale, but for star Johnny Galecki, it was more of a win for “Roseanne” than the long-running CBS sitcom.