The Dallas star proved his directorial chops by helming almost 30 episodes of the classic TV drama during its original run, and he also took the chair for almost 50 episodes of his 1990s comedy Step by Step.

Now he has revealed to fans that he is directing an episode of U.S. police procedural show Major Crimes, which stars Mary MCDonnell as the new head of a serious criminality unit.

Explaining his three-month absence from Twitter.com, Duffy took to the microblogging site to post a photograph of himself holding a clapperboard for Major Crimes, which lists him as director.

In a caption alongside the image, he writes, "My reason for being absent. Loving directing Major Crimes!!"