Buffy's Alyson Hannigan Wasn't The Original Willow - Here's Who She Replaced

"Buffy the Vampire Slayer" pretty much changed everything when it came out in the late '90s. Though genre TV in the vein of fantasy, science fiction, and horror had often been a bit of a dark horse on the small screen, the massive cult success of Joss Whedon's teen drama series showed that shows like this could break into the highly coveted teen and early 20s age demographic.

Of course, "Buffy the Vampire Slayer" was nothing without its compelling cast of characters, played by actors who have since become household names, like Sarah Michelle Gellar and David Boreanaz. The series had one of the hottest young casts in the business, and Alyson Hannigan's earnest and sweet performance as the bookish Willow was among the show's biggest stand-outs.

That's why it's a bit of a surprise to learn that she wasn't the original choice for Willow on "Buffy the Vampire Slayer." So, who was? Well, that would be Riff Regan. The actor played Willow in an unaired pilot of the series, and it was also her last role as a performer. Regan had previously appeared in episodes of "Dr. Quinn, Medicine Woman," "Blossom," and "Roseanne."

Riff Regan played Willow in the 30-minute pilot version of "Buffy the Vampire Slayer" that Joss Whedon used to sell the series. However, when it went forward for Season 1, there were a few changes that were made, including the name of the school, Buffy's (Sarah Michelle Gellar) hair color, and, of course, Willow.

Why was Riff Regan replaced by Alyson Hannigan?

It seems like Whedon wanted an actor who also had a bit of spunk on top of fitting the bill as the timid Willow earlier in the series. Enter Alyson Hannigan. Clearly, the new character was a success, considering she was in almost every episode of "Buffy the Vampire Slayer" across the show's seven-season run. Furthermore, considering the darkness and angst that colored Willow's later storylines in the series, it looks like the change was an effective one, even if some fans balked at her Season 6 arc.

Others who have seen the original "Buffy the Vampire Slayer" pilot also note that Regan lacked the poppy chemistry that was needed for Whedon's snappy back-and-forth dialogue and the general flow of the show. Either way, with how much Willow came to define the series, few fans will argue that the new direction for the character was the right way to go.

After all, between "Buffy the Vampire Slayer" and "American Pie," Hannigan proved herself to the point where she practically became a household name. Furthermore, her knack for playing likable geeks helped her land the role of Lily on "How I Met Your Mother," another long-running series that featured her in every episode.