Thomas Lawrence Knight (born 22 January 1993),^[1][2] usually credited as Tommy Knight, is an English actor best known for playing Luke Smith in The Sarah Jane Adventures and Doctor Who, Kevin Chalk in the original run of Waterloo Road, Cal Bray in Glue and Archibald Brodie in Victoria.

Born in Chatham, Kent, Knight is the middle of five siblings, all of whom act.^[3] He attended Delce Junior School in Rochester from year 4 onwards and formerly attended the Sir Joseph Williamson's Mathematical School.^{[citation needed]}

Knight was in a relationship with Waterloo Road co-star Abby Mavers from 2012 to 2017.^[4]

Knight started in West End Theatre with Deborah Warner's production of Euripides' Medea, (Queens Theatre, 2001),^[5] and has since appeared in Chitty Chitty Bang Bang, (London Palladium, 2002),^[5] The Snowman, (Peacock Theatre, 2003),^[5] The Full Monty, (UK National Tour, 2004)^[5] and the Royal Shakespeare Company's Macbeth (Albery Theatre, 2005).^[5]

Additional television performances include roles in TV to Go, (BBC, 2002),^[6] Casualty, (BBC, 2005, 2007 and 2015),^[6][7] The Impressionists, (BBC, 2006),^[8] Sorted,^[9] (BBC, 2006), Doctors (BBC, 2006),^[10] and The Bill (Talkback Thames, 2006 and 2009),^[11] and Myths (BBC, 2008).^[12]

Knight is best known for playing Luke Smith, adoptive son of Sarah Jane Smith, in the first three series of The Sarah Jane Adventures (2007, 2008, 2009) and in the 2008 Doctor Who episodes "The Stolen Earth" and "Journey's End". He was featured in the second part of "The End of Time", the two-part 2009 Doctor Who Christmas specials.^[13] He was written out as a regular on The Sarah Jane Adventures in the first serial of the fourth series in 2010, when Luke drives off to Oxford University, however he continued to make semi-regular appearances in the show up to the end of the fifth and final series, usually via webcam from his dorm room. His final appearance was in the show's final episode, "The Man Who Never Was".

He also featured in a CEOP e-Safety Video "Tom's Story", which can be watched on YouTube. Knight featured in a darker role in a 2012 independent UK horror film, A Suburban Fairytale, in which he acted alongside real life sister Yohanna Farrel in an incestuous and murderous role.^{[14][non-primary source needed]} He joined Waterloo Road in 2012, first appearing in episode 8 of series 8 playing Kevin Skelton. His notable storylines included being adopted by teacher Daniel Chalk (and thus changing his name to Kevin Chalk), his relationship with Dynasty Barry, having an affair with a teaching assistant and most recently suffering a stroke before a university interview. He left Waterloo Road in Series 10 Episode 12.

In 2014, he appeared as murder victim Cal in the E4 drama series Glue. He later played Hall Boy Brodie in Victoria, a period drama starring Waterloo Road and Doctor Who alumnus Jenna Coleman.^[15]

In March 2023, in an interview with Knight in Doctor Who Magazine, Knight says he no longer acts and is now a computer coder, offering tech support as well;^[16] however, this is disputed by Knight's own LinkedIn page, crediting him as still acting.^[17] As of 30 March, 2024, his LinkedIn page describes him as a Front-End Developer with no mention of acting.