Betty Lynn
Elizabeth Ann Theresa Betty Lynn is a former American actress. She is known for having played Thelma Lou on The Andy Griffith Show. She, along with Elinor Donahue, is one of the two surviving regular female cast members of that show.
Lynn was born in Kansas City, Missouri, and began acting in radio. She was later discovered in a Broadway production by Darryl F. Zanuck and signed to 20th Century Fox. Lynn made her film debut in the 1948 film Sitting Pretty opposite Robert Young. That same year, she appeared in June Bride with Bette Davis followed by roles in Mother Is a Freshman , Cheaper by the Dozen , and Payment on Demand .
Source: Wikipedia