Robin Williams to guest on 'L&O: SVU'

Robin Williams is to guest star in the 200th episode of Law & Order: SVU.

The landmark show, which will air late next month in the US, will see Williams take the role of an engineer gone off the rails.

A tragedy causes him to challenge authority and attempt to find others to join his cause. Executive producer Neal Baer, who co-wrote the script, said it was "powerful and complex".

Williams previously won an Emmy nomination for a guest appearance in Homicide: Life on the Street.