Is there a precedent for casting the same actor in an American remake of a British/foreign television show?

It's quite a rare occurrence, with two major exceptions: comedies and factual programmes.

Comedy remakes:

• Red Dwarf which was remade in the USA (one pilot episode) with Robert Llewellyn as Kryten in both versions, and he was also joined by the original series writers, Rob Grant and Doug Naylor.
• The IT Crowd also suffered a US pilot in which Richard Ayoade reprised his role as Moss.
• Max Headroom was an American series based on a British TV pilot Max Headroom: 20 Minutes into the Future which starred Matt Frewer as the title character in both versions.
• Little Britain was re-made/continued as Little Britain USA which starred both Matt Lucas and David Walliams as nearly every role.
• Da Ali G Show with Sacha Baron Cohen as Ali G. Season 1 was produced by Channel 4 and sold to HBO, Season 2 (Ali G in da USAiii) was produced by HBO and sold to Channel 4.
• Whose Line Is It Anyway? shared several panellists in common with the US version; Ryan Stiles, Colin Mochrie and to a lesser extent Wayne Brady.
• Wilfred is a remake of the Australian series which both star Jason Gann as Wilfred.

Factual remakes:

• The Weakest Link was hosted by Anne Robinson in the original and US remake.
• Distraction was hosted by Jimmy Carr in both the original and US remake of the show.
• Gordon Ramsay started in the British Hell's Kitchen in 2004 for one season before going to the US to present the remake in 2005.
• How Clean Is Your House? was remade in the US with Kim & Aggie presenting both.
• Pop Idol / American Idol with Simon Cowell as a judge.
• The X Factor was also remade in the US with Simon Cowell.
• The talk show Trisha Goddard was remade in America as The Trisha Goddard Show
• Supernanny with Jo Frost in the UK and US version.

It also less commonly happens the other way around, though most of the examples I can find are American shows which were hosted by British actors before being remade in Britain:

• America's Got Talent was remade in the UK as Britain's Got Talent, with Piers Morgan judging both.
• So You Think You Can Dance is hosted by Cat Deeley in the US and UK versions.
• The Taste was remade in the UK with the same judges; Anthony Bourdain, Nigella Lawson and Ludo Lefebvre

In both cases its easy to see why: the cast hold together the show and are usually the ones responsible for making the show famous, so it's a no-brainer that you want to get as many of them as possible to help sell your show, especially if they're the only presenter.

See also:

• Foreign Remakes on TVTropes
• Remake Cameo on TVTropes
• Category:American television series based on Australian television series on Wikipedia
• List of American television series based on British television series on Wikipedia

Anthony Stewart Head, famous for playing Giles on Buffy the Vampire Slayer, plays the character of Stephen Caudwell on Free Agents, the foul-mouthed head of the advertising agency.

Two years later, the show was remade in the US with Hank Azaria and Kathryn Hahn instead of Stephen Mangan and Sharon Horgan, and some other changes to characters and plotlines, but one thing remained the same - Anthony Head still played the same role of Stephen, head of the agency.

Of course, American network TV being what it is, he was significantly toned down in obnoxiousness and vulgarity.

The UK series Ultraviolet (late 90's Vampire series) featured Idris Elba.

He was cast in the unaired pilot episode of a US remake (as the same character).