Tiffani Amber Thiessen (born January 23, 1974) is an American actress. Her roles as Kelly Kapowski on NBC's Saved by the Bell (1989–1993) and its spin-off media, and as Valerie Malone on Fox's Beverly Hills, 90210 (1994–98) established her as a teen idol of the 1990s. As an adult, she has played Wilhemina 'Billie' Chambers in Fox's Fastlane (2002–2003), Natasha Drew in ABC's What About Brian (2007), Elizabeth Burke in USA Network's White Collar (2009–2014), and Lori Mendoza in Netflix's Alexa & Katie (2018–2020). For the latter, she earned a Daytime Emmy Award nomination.

Thiessen has appeared in several films, such as Son in Law (1993), Speedway Junky (1999), From Dusk Till Dawn 2: Texas Blood Money (1999), Love Stinks (1999), Ivans Xtc (2000), Shriek If You Know What I Did Last Friday the 13th (2000), The Ladies Man (2000), Hollywood Ending (2002) and Cyborg Soldier (2008). She directed the short film Just Pray (2005), for which she earned a nomination from the Tribeca Festival for Best Narrative Short. She hosted the Cooking Channel series Dinner at Tiffani's (2015–2017) and the MTV comedy clip show Deliciousness (2020–present).