Special Guest Stars -- A TV Trick That Goes Back a Long Way

Robin Williams is tonight's special guest star on NBC's Law & Order: Special Victims Unit (10 p.m. ET), playing a tightly wound guy who manipulates people into doing sinister things. Eventually, he gets pulled into the court, defends himself -- and the story doesn't end there.

It's a big, showy part. A bit too showy, actually. In the world of SVU, which usually plays fairly realistically, Williams' character is more like a villain from the old Batman TV series -- thinking eight steps in advance, setting up elaborate traps and tests, always having an escape hatch nearby. There's even a scene where he gets famous enough to go on Joe Scarborough's Morning Joe, as a courtroom celebrity, with a sheep in tow. And the detectives from SVU watch him on TV.

It's nice that the detectives of an NBC series make a habit of watching an MSNBC morning talk show. It's not quite as implausible as when the terrorist-hunting experts on the Fox drama series 24 keep their TV monitors tuned to Fox News -- but still. Yet the guest spot itself, in a grand way, is show business, too. Watch for Williams to be nominated for an Emmy in the Guest Actor character later this year. Doubtlessly, it was written, and accepted, with that in mind.

When did this trend begin? Not recently. Williams himself did a similar showy guest shot in 1994, when Barry Levinson, co-executive producer of Homicide: Life on the Street, talked his old Good Morning, Vietnam star into appearing in an episode. (Williams was nominated for an Emmy then, for Outstanding Guest Actor in a Drama Series, but didn't win.) And it goes back long before that.

Before those one-shot or recurring roles were given their own Emmy categories, actors could swoop in on existing series, knock a guest role out of the park, and walk away winning a Supporting Actor or Actress award -- competing against regulars who toiled for the entire year on their series and character. It may not have been fair, but it was fun. On St. Elsewhere, in its first season in 1982-83, both James Coco and Doris Roberts guest starred as homeless people in love -- and both of them won Emmys.

That same season of St. Elsewhere also introduced a recurring character and actor who didn't win an Emmy that year, but who played a very memorable role, has enjoyed a strong and multi-faceted career since, and has been a star of this blog recently: Tim Robbins. In the first episodes of St. Elsewhere, he played an angry radical bomber... very, very memorably.

And long before that, Robert Altman once told me that when he directed episodes of the 1960s TV WWII series Combat, and a script called for a new character -- a one-shot guest spot in more ways than one -- to be killed or wounded in action, Altman would hire the actor a few episodes earlier, and lace him into the stories and action just so viewers would get to know him a little. Then, Altman said, the death would be more surprising, and have more dramatic resonance.

Altman was on to something then -- and TV has been stealing from his playbook ever since.