And the executive producer has promised that Luke's "wise and vivacious" spirit will live on through the show, even though he knows it will never be the same without him.
He added: "Luke was, is, and will always be a big part of 'Riverdale'.
"We're kind of a family and when a loss like this happens, you carry it always. It changes and it hopefully becomes a little less painful as time goes by, but you're changed.
"When I was with the crew, I said, 'It will never be the same,' and that's true because Luke was such a part of the show.
"There are still a few more episodes that have Luke in them, so we're glad to share those.
"His spirit -- which was so generous and wise and vivacious -- we hope will infuse every episode, so in my mind, every episode for the rest of time on 'Riverdale' will have a bit of Luke in it."
Shortly after the actor passed away, Roberto announced all the remaining episodes of the current season of the CW drama would be dedicated to Luke.
He tweeted: "Going through pictures on my way to set. From the early days. With Luke in the middle. Our heart, always. Tonight's episode of #Riverdale finds Fred doing what he does best - helping Archie. It is dedicated to Luke, as all episodes will be for the rest of our run. (sic)"
