Michael Dorn has played the Klingon Worf for several Star Trek films and series, although fans shouldn't expect to see him reprising the role on Star Trek: Discovery. Beyond the fact that adult Worf appearing in a pre-OG Star Trek series would be problematic to canon, to say the least, Dorn doesn't appear too willing to sit in the makeup chair for that long. The actor stated he's fine with not playing a Klingon on the CBS All Access series, especially after watching what actress Mary Chieffo had to go through to become L'Rell in Season 1:
I am actually really glad that I am not in that makeup, because if you go online and look up YouTube of Mary Chieffo -- just a wonderful, just a sweetheart, but what they do to that poor girl is mind-boggling. There are three makeup artists working the whole time on her...I mean, it's okay. It's just another iteration.
Michael Dorn hinted that the makeup process for Klingons on Star Trek: Discovery seemed far more labor-intensive than his makeup job to become Worf, and that he took pity on Mary Chieffo. Dorn chose his words carefully, undoubtedly well aware that the show's radical change of Klingon appearance has been a touchy subject for fans and critics. Dorn didn't tip his hand too far in revealing how he felt about the new look but did remind attendees at the Rose City Comic Con (via Trek Movie) that each series has changed the Klingons in some way.
That statement might lead some to believe that Michael Dorn is in favor of the new Klingons, although the actor followed up later with another comment that makes it appear his stance on the costumes is far more middling. Dorn got into a conversation with fellow co-star, actress Gates McFadden, about how little of a Klingon actor's real face is actually visible during scenes, and how that could affect their acting ability:
That is the problem. There is nothing of her, at all...Nothing. Just her eyeballs. That's it.
Michael Dorn isn't exaggerating there, as Star Trek: Discovery videos have shown the eyeballs are about the only visible facial feature on Mary Chieffo once she was fully suited up as L'Rell. In spite of that, there were few complaints about Chieffo's portrayal of L'Rell in Season 1 of Star Trek: Discovery and her facial expressions seemed far less limiting than Dorn's statement would imply. It is fair to say her face is far more hidden by makeup than Dorn, who had his eyes, cheeks and mouth largely untouched by the Star Trek team when he played Worf. At the end of the day, Dorn doesn't have to worry about it, especially considering nothing we've heard about Season 2 involves him making a cameo.
Season 2 of Star Trek: Discovery is expected to air on CBS All Access in 2019. Keep track of all major television shows arriving before that by visiting our fall premiere guide.