14. Melissa Rauch: Then
When Melissa Rauch joined the cast of TBBT as Bernadette Rostenkowski, it was 2009, two years into the series. They introduced her character as a friend of Penny’s from The Cheesecake Factory, but audiences quickly learned that there was more to Bernadette than making tips. She had her Ph.D. in microbiology. She also quickly came under the charms of Howard, mostly over their shared experiences with overbearing mothers.