William Shatner played Captain James T. Kirk on Star Trek 

William Shatner may be best known for his role in Star Trek, but the veteran actor has never even seen an episode of the iconic show. 

Shatner, who turned 90 this week, told Jeremy Parsons on People (the TV Show!) on Tuesday that it's too "painful" to watch himself act as Captain James T. Kirk in the series, which originally aired from 1966 through 1969.

"I have never watched Star Trek," he said. "There are many episodes I don't know, there are some movies I don't know." 

He added that he did watch one of the franchise's many movies, Star Trek V: The Final Frontier, but only because he directed it. 

William Shatner in Star Trek
William Shatner in Star Trek
| Credit: CBS Photo Archive/Getty

"I directed one of the movies — No. 5 — I had to watch that one," he said. "But it's all painful because I don't like the way I look and what I do." 

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Shatner is currently preparing for the release of his latest project, Senior Moment, on March 26. Last month, PEOPLE got an exclusive first look at the upcoming film, which features Shatner as Victor, a retired NASA test pilot whose license gets taken away after he's found speeding in his vintage Porsche convertible with his best friend Sal (Christopher Lloyd). 

His life changes as he finds himself trying to get around by riding the bus, spurring his meeting with the beautiful free-spirit Caroline (Jean Smart). 

William Shatner
Credit: Greg Doherty/Getty

Shatner previously told PEOPLE his chemistry with Smart, 69, was "the same as phosphorus and water. An intense fiery meeting that generates light and heat to an enormous degree and just as suddenly is extinguished because remember we are both a little older."

Smart said the two had previously had "a lot of fun" on Shatner's 2010 series $#*! My Dad Says where they played warring neighbors who eventually fell in love.

"In Senior Moment we play characters who are so different with such different lifestyles that it's fun to see them negotiate a romance; as a friend of mine says: 'They fill in each other's gaps,'" she said.