Like most of Hollywood, Green was left devastated after learning Perry had died five days after suffering a stroke at his home in Sherman Oaks, California.
Brian was criticised for not posting a public tribute to Luke in the days following the former TV pin-up's passing and fans and followers took aim at him last week, ends March 15, after he broke his social media silence to promote an upcoming "Beverly Hills, 90210" podcast reunion, which is set for late August.
But now it seems he paid his tribute to his late friend in private, sending him a text and explaining just how much he meant to him.
"Luke was a special guy," Brian said in his latest podcast. "I'm still mourning over it, so there's a part of me that's kind of shocked that I'm speaking about Luke this way. We all knew that at some point we'd have to deal with losing cast members and friends, but not this soon. Not at 52. Not in such an abrupt way."
"I texted him after he passed, knowing obviously that he can't text me back but on some level, hoping that he would text me back, or that he was out there somewhere," Brian added. "And I know he is. I know he's looking down and I know he's smiling."
He also told listeners, "Luke was one of those people nobody had a bad story about. He was just a great guy. And he was Luke no matter where you saw him, no matter when you saw him, no matter what he was going through. He was a rock."