Charlie Sheen is looking back on one moment of his life with regret … and that is not reaching out to pal Matthew Perry before his death.

The actor opened up about his connection with the late “Friends” star, revealing he wanted to reconnect with the funny man in 2023 after reading Matthew’s memoir, “Friends, Lovers, and the Big Terrible Thing.”

Sheen told Page Six … he was thrilled to be included in Perry’s book, which detailed the highs and lows of the actor’s addiction, something CS knows a thing or two about.

While Sheen noted he never did ketamine — the drug at the root of Perry’s fatal overdose in October 2023 — he revealed Perry had hosted a support group for addicts, and over they years, Charlie attended some of the meetings.

He added … “Matt and I shared a deeper truth we saw in each other … we were both, as [Robert Downey Jr.] used to say, ‘veterans of the unspeakable.’ … We had that common ground instantly with each other.”

And so, after reading Perry’s “brilliant” memoir, Sheen said he felt compelled to reach out, and ask him for a coffee meet up, but never got around to shooting him that message.

Sheen now regrets not following through on this plan, as, just 3 weeks later, Perry died at the age of 54.