WATCH | Celebrating its 20th anniversary March 10, TV's "Buffy the Vampire Slayer" solidified the star power of Sarah Michelle Gellar, David Boreanaz, Alyson Hannigan and Seth Green. But they aren't the only stars to make a name for themselves after appearing on the show.
"Harold and Kumar" headliner Kal Penn, "Dr. Horrible's Sing-Along Blog" star Felicia Day and five-time Oscar nominee Amy Adams are among the actors to have guested on the series on their way to greater stardom.
Adams, once a frequent WB/CW guest star, played Tara MacLay's cousin Beth in Season 5.
Penn played Hunt, who grabs a drink with Buffy in Season 4.
Day played Violet, a fellow Slayer, in Season 7.
"The Sisterhood of the Traveling Pants" star Amber Tamblyn played Janice Penshaw in Season 6.
"Prison Break" star Wentworth Miller played a high-school swimmer named Gage in Season 2.
"The OC's" Rachel Bilson played Colleen, a Potential Slayer, in Season 7.
WATCH | Also turning 20 this month is the hit MTV series "Daria," whose star and co-creator recently chatted with Circa about that show's history and legacy.