Angela is an FBI agent who does a background check on Howard when he needs a security clearance to be on the Defense Department Equipped Surveillance Satellite Team.
When she interviews Raj about Howard, Raj is paranoid and only talks about himself, sharing with her that he is definitely legal in the U.S. Then, Leonard hits on her but learns that she is married to a Navy Seal. When Angela interviews Sheldon, he accidentally tells her that Howard once crashed the Mars rover to try and impress a girl. Needless to say, Howard didn’t pass the security clearance to be on the team.
Riki Lindhome as Ramona Nowitzki – Then
Ramona works at Caltech as a postdoctoral researcher and is a big fan of Sheldon and his work. She meets him in the cafeteria, and they arrange to have dinner at his apartment.
His friends feel that she is a bit obsessive, but Sheldon just appreciates that he’s getting free dinner. During their date, the rest of the gang sits on the couch as onlookers of this strange turn of events. Eventually, Sheldon solves the problem that he’s working on, and Ramona wants to share credit for it. He reacts by kicking her out of the apartment.
Riki Lindhome as Ramonda Nowitzki – Now
Riki’s most well-known roles are in the movies "Million Dollar Baby" and "The Last House on the Left." She has played Beatrice in the historical comedy series "Another Period" from 2013 to 2018. She also was the voice of the character Poison Ivy in the newest "Lego Batman Movie."
The actress also acted in a thriller movie called "Under the Silver Lake," alongside Andrew Garfield and Riley Keough (Elvis’s granddaughter).
Eliza Dushku as Angela Page – Now
Eliza definitely didn’t start her career in TBBT. When she made her appearance on the series, she was already a well-known name in Hollywood.
She played Missy Pantone in the popular cheerleading movie "Bring It On," as well as Faith in the "Angel" and "Buffy the Vampire Slayer" Series. She had a lead role in the Fox series "Dollhouse" as Echo and another lead as Tru in "True Calling." She hasn't been acting since 2017.
Courtney Henggeler as Missy Cooper – Then
Missy is Sheldon’s fraternal twin sister, who is completely different than her brother. While she is very charming and amicable, Sheldon is anything but. She is introduced in the first season, with Leonard, Howard, and Raj all crushing on her.
The men fall over each other, trying to win her attention, and Sheldon tells them that he will choose who gets to date her. Missy finds an ally with Penny, and while they are hanging out at her apartment, each of the guys tries their luck at asking her out, but none of them are successful.