Kathryn Felicia Day (born June 28, 1979)[1][2] is an American actress, singer, writer, and web series creator.

[3][4] On television, Day has played Vi in the series Buffy the Vampire Slayer (2003) and Dr. Holly Marten in Eureka (2011), and had a recurring role as Charlie Bradbury on Supernatural (2012–2015, 2018–2020).

[6][8] An accomplished violinist,[6] Day was accepted to the Juilliard School of Music but chose to attend the University of Texas at Austin on a full scholarship in violin performance.

Much of her work on The Guild web series was based on her personal experience with video games, especially when she played World of Warcraft.

She landed several roles in various short and independent films as well as commercials and guest spots on television shows, including Undeclared and Maybe It's Me.

In HBO's 2005 biopic of Franklin D. Roosevelt, Warm Springs, Day's singing was featured when her wheelchair-using character serenaded a dinner group with "I Won't Dance".

Day is the creator, writer, and star of The Guild,[13] a web series which aired from 2007 to 2013 and explored the MMORPG gaming subculture.

Day also created a song and music video called "(Do You Wanna Date My) Avatar", featuring the cast dressed up as their in-game personae.

In the same vein, in 2015, she suggested to the original cast of Critical Role to begin streaming their tabletop home game as a show.

[23] In August 2014, Geek and Sundry was acquired by Legendary to produce content alongside of Chris Hardwick's Nerdist Industries,[24] with Day retaining creative control.

On January 11, 2016, Chinese conglomerate Wanda Group announced that it concluded an agreement with shareholders to acquire Legendary Entertainment for $3.5 billion.

[34] Day also played the continuing role of Dr. Holly Marten in the Syfy channel's original series, Eureka, appearing in 18 episodes during the last two seasons of the show.

[36] Day plays an elf named Tallis, and returns as the voice and likeness for the character in the Dragon Age II downloadable content Mark of the Assassin.

[37] Also in April of that year, Day appeared on the YouTube show MyMusic as a Norwegian Black Metal singer named Gorgol.

[43][44] Day organized and hosted a Twitch charity livestream on June 30, 2018, in aid of Refugee and Immigrant Center for Education and Legal Services (RAICES), a Texas nonprofit.

[49] She also interviewed cast members for a panel at New York Comic Con, which was recorded and released as a bonus episode of the podcast in November 2022.