Hollywood icon Jack Nicholson is devastated over the death of Diane Keaton — and friends fear he could be next.

The Shining star, 88, is now struggling to deal with the fact he never got to bid farewell to his 79-year-old friend and colleague.

“He’s stunned and very cut up over her passing, it feels like he’s lost a sister,” an insider tells Globe.

The two costarred in 1981’s Reds and the 2003 smash hit Something’s Gotta Give, which is when they really bonded, the insider says. “It was one of Jack’s last big hurrahs in Hollywood before he went into full-blown retirement.”

 <span class="wp-caption-text">Sony Pictures Releasing</span>

Sony Pictures Releasing

“He couldn’t have asked for a better experience than working with her — they also spent a good amount of time together off set. He would confide in her and vice versa,” the source says.

The two stayed in touch for years afterward as well — she was one of the few people in his world whom he felt he could fully open up to, the insider says.

But with her death has come a real fear Jack may not have much time left either.

As readers know, he has cut an increasingly reclusive figure since retiring from acting in 2010.

Not only has he repeatedly turned down comeback offers, he rarely socializes or ventures out of his home in the Hollywood Hills, which has only fueled fears he’s suffering from a serious illness.

 <span class="wp-caption-text">Getty Images</span>

Getty Images

In one rare sighting in 2023, shutterbugs captured the legend looking bedraggled and out of sorts while gazing into space from the balcony of his luxury mansion — sparking more fears about his well-being.

“Jack has led an incredible life and a lot of people would agree he’s pretty lucky to still be around after all the partying he did in his heyday,” notes an insider.

“Sadly, he’s at an age now where a lot of his friends and contemporaries are passing away, and that’s a very painful reality for him to be dealing with,” the insider says.

“He’s a fighter, but at the end of the day he’s only human.”

This story Jack Nicholson ‘Stunned’ by Longtime Pal Diane Keaton’s Death: ‘It Feels Like He’s Lost a Sister’ first appeared on Globe. Add Globe as a Preferred Source by clicking here.