Vilanch recently voiced his opinion about the performance, suggesting Franco had been juggling too many responsibilities to give the gig his all.
The actor took aim at Vilanch by posting a photo of the pair on his Twitter.com page and writing "James f**ked up the Oscars. Trust me, I know comedy. I mean, come on, I write for Bette Midler!" over the writer's face.
The post was later removed, but not before it was picked up by various blogs online, prompting Vilanch to reach out to Franco.
The writer explained his comments were made in jest in a "much lighter" tone, adding, "I would never diss you, that's not my style."
Franco conceded he had made a mistake by getting caught up in the gossip and issued an apology of his own to Vilanch, writing on Twitter: "Thanks Bruce. Sorry for reading stupid blogs. James."