"I had been reading television and film [scripts] and this was so well written I thought, 'Wow, I have to do this,'" Berry tells TVGuide.com.
Another huge factor? Executive producer Steven Spielberg. "He is the king!" she adds. "I desperately wanted to work with him."
Premiering on Wednesday (9/8c, CBS), Extant is about an astronaut (Berry) who comes home from a 13-month solo mission and learns that she is pregnant. And that's only the beginning of the show's bizarre mysteries that include strange occurrences while in space and her young son's theory of impending extinction.
"What happened? How did it happen? Is it my egg? Is it an offspring? There are all these questions we have to answer," she says.
Watch Berry talk about the series:
(Full disclosure: TVGuide.com is owned by CBS.)