William Shatner is getting vulnerable about mortality.

In a recent profile with Variety, the 91-year-old “Star Trek” actor expressed that he doesn’t “have long left to live” while discussing his new documentary “You Can Call Me Bill”. 

“You Can Call Me Bill” chronicles the actor’s career highlights, ranging from his time on “Star Trek” to the series “T.J. Hooker” and “Boston Legal”.

READ MORE: William Shatner Speaks Out About Former ‘Star Trek’ Co-Stars Publicly Criticizing Him: ‘It’s Like A Sickness’

Shatner explains how he hopes his documentary will speak to his grandchildren as they get older.

“I’ve turned down a lot of offers to do documentaries before. But I don’t have long to live. Whether I keel over as I’m speaking to you or 10 years from now, my time is limited, so that’s very much a factor. I’ve got grandchildren. This documentary is a way of reaching out after I die,” explained the actor regarding his choice to release a documentary.

Shatner further shared his thoughts that long after an actor dies, the only thing that lives on past them are their good deeds.

READ MORE: William Shatner Reflects On His Devastating Fallout With Leonard Nimoy Before His Death

“Who remembers Danny Kaye or Cary Grant? They were great stars. But they’re gone and no one cares. But what does live on are good deeds. If you do a good deed, it reverberates to the end of time. It’s the butterfly effect thing. That’s why I have done this film.”

“You Can Call Me Bill” will premiere at SXSW.