Dianna Elise Agron is an American actress, singer, dancer and occasionaly a producer, writer and director. She made her debut appearing as Jessica Grant in CSI:NY. She potrayed Sarah Hart in the movie adaptation of I Am Number Four. Agron was born in Savannah, Georgia and was raised in San Antonio, Texas and San Francisco, California. Her parents are Mary and Ronald S. Agron. 

When Dianna was growing up, she spent much of her time performing. She began dancing at the age of three, focusing mainly on jazz and ballet. She later began hip hop dancing as well. Dianna also spent much of her time performing on stage, appearing in many local music theater productions when she was younger.

Agron has appeared on television shows such as Shark, Close to Home, CSI: NY, Numb3rs, and had a recurring role on Veronica Mars. She then appeared as Harper on a 13-episode series of short films called It's a Mall World, directed by Milo Ventimiglia, and airing on MTV, and then on the second season of Heroes as Debbie Marshall, the head cheerleader/captain of the cheer squad at Costa Verde High School. Dianna has also hosted a mini Music Festival for 826LA in Los Angeles called "Chickens in Love." Agron's most notable role to date is as Quinn Fabray, a high school cheerleader, on the Fox series Glee. Agron was the last primary actor to be cast, having won the role only days before the pilot began filming. Agron said in a 2009 interview pertaining to her casting session: "I nearly bailed on my audition for the show. I was so nervous".

Agron is a vegetarian, and has supported PETA and gay rights.Agron worked with The Trevor Project in 2012 to raise money in honor of her birthday. In 2012, Agron visited the Kampong Cham Center, where she met children and teenage residents. On April 20, 2013, the people honored Dianna by raising $10,200 for her birthday, benefiting the Somaly Mam Foundation in effort to fight human trafficking. Agron donated possessions to the Vietnam Veterans of America in Los Angeles during August 2013. Agron also supports the initiative between Camp Wonder and Cetaphil, which is about children with chronic and life-threatening skin diseases to enjoy being a kid.

Agron and Alex Pettyfer, who incidently played her on screen love interest John Smith/Number Four, had a relationship which ended in February 2011.