Mark Williams
Mark Williams (born August 22, 1959) is an English actor, comedian, presenter and screenwriter. He first achieved widespread recognition as one of the central performers in the popular BBC sketch show The Fast Show. His film roles include Horace in the 1996 adaptation of 101 Dalmatians and Arthur Weasley in seven of the Harry Potter films. He made recurring appearances as Brian Williams in the BBC television series Doctor Who and as Olaf Petersen in Red Dwarf. Since 2013, Williams has portrayed the title character in the long-running BBC series loosely based on the Father Brown short stories by G. K. Chesterton.
Where to watch Mark Williams’s work in 
United States
Top 30 by popularity. Click any title to see exactly which OTT carries it in United States.
Midsomer Murders
1997
Doctor Who
2005
Top of the Pops
1964
Casualty
1986
Harry Potter and the Chamber of Secrets
2002
Harry Potter and the Deathly Hallows: Part 2
2011
Father Brown
2013
Harry Potter and the Deathly Hallows: Part 1
2010
Harry Potter and the Goblet of Fire
2005
Harry Potter and the Prisoner of Azkaban
2004
New Tricks
2004
Harry Potter and the Half-Blood Prince
2009
Agatha Christie's Marple
2004
Peak Practice
1993
Merlin
2008
Loose Women
1999
Harry Potter and the Order of the Phoenix
2007
Hustle
2004
The One Show
2006
Red Dwarf
1988
The Musketeers
2014
Sister Boniface Mysteries
2022
Being Human
2009
Early Man
2018
Harry Potter 20th Anniversary: Return to Hogwarts
2022
101 Dalmatians
1996
Stardust
2007
Sense and Sensibility
2008
The Storyteller
1988
Comedy Lab
1998