Comedian and actor Albert Brooks said he's still in shock over the death of one of his oldest and best friends, Rob Reiner.

"Rob was my oldest friend. It's that simple. He's the person that I've known the longest. I met him when I was 14 years old. So I'm still in that not believing it stage," he told CBS News in the upcoming special "CBS News: Rob Reiner - Scenes from a Life," airing Sunday. Brooks and Reiner met at Beverly Hills High School in a drama class 60 years ago.

Reiner and his wife, Michele, were found fatally stabbed in their Los Angeles home on Dec. 14, authorities said. Their son, Nick, has been charged with first-degree murder in their deaths.

Brooks said there are still moments he forgets his friend is gone.

"I know it happened, but, you know, I'm driving around and all of a sudden – I actually two days ago, I called his number," he recalled.

Brooks and Reiner returned to their high school, reminiscing about their time together while surveying the school's Wall of Fame, during an interview for "CBS Sunday Morning" in December 2023. 

"This is the first time both of us have been back since we graduated," said Reiner. Brooks joked: "Over a certain age, it's against the law. Well, life works best when you remember." 

As they pointed out a bench they used to sit on, Reiner joked, "It brings back no memories," as Brooks agreed, "Nothing. Nothing."

Reiner directed the HBO documentary, "Albert Brooks: Defending My Life," released in 2023. Before that, the pair was only in one movie together, "The Muse" in 1999. "He hired me. He was nice enough to hire me," Reiner said. "I was," Brooks replied.

You can hear more from Brooks and others who knew Reiner in the one-hour special "CBS News: Rob Reiner - Scenes from a Life." It will be broadcast Sunday at 8:30 p.m. ET/8 p.m. PT on CBS, and will stream on Paramount+.