Apparently, even Keanu Reeves was taken aback by Matthew Perry asking why he “walks among us.”

“Keanu thought the comments came out of left field,” a source told Us Weekly Friday about the multiple mentions of the “Matrix” star in Perry’s new memoir.

“It’s kind of backfired on Matthew anyway, which is why he had to apologize,” the source added.

The “Friends” alum, 53, issued a mea culpa to Reeves, 58, in the days leading up to the Nov. 1 release of “Friends, Lovers and the Big Terrible Thing.”

“I’m actually a big fan of Keanu. I just chose a random name, my mistake. I apologize,” he told People. “I should have used my own name instead.”

In the book, Perry details working with the “John Wick” star’s best friend River Phoenix on the 1988 film “A Night in the Life of Jimmy Reardon.”

Perry and Phoenix played best friends in the movie and became close in real life, but the “Stand by Me” star died of a drug overdose at 23 years old in 1993.

Matthew Perry's "The End Of Longing" - Photocall
The "Friends" alum apologized for asking why Reeves still "walks among us."

“Why is it that the original thinkers like River Phoenix and Heath Ledger die, but Keanu Reeves still walks among us?” the “17 Again” star writes.

“River was a beautiful man inside and out and too beautiful for this world, it turned out. It always seems to be the really talented guys who go down.”

Perry doubles down on the Reeves dig later in the memoir when he recalls his initial reaction to his “Almost Heroes” co-star Chris Farley’s fatal overdose in 1997.

“I punched a hole through Jennifer Aniston’s dressing room wall when I found out,” he writes. “Keanu Reeves walks among us.

Perry and Reeves never publicly had a falling out, so the harsh comments turned heads and even led to speculation that the former had a bizarre obsession with the latter.

Elsewhere in his bombshell memoir, Perry goes into detail about “nearly” dying in 2018 when his colon burst, his ill-fated dating history with celebs like Cameron Diaz, Julia Roberts and “Friends” co-star Aniston as well as his decades-long struggle with drug and alcohol abuse.