Remember when 90s-era “It” Girl Alicia Silverstone headed for the Hills kicking and screaming when she was faced with the prospect of co-starring with Britney Spears in the March 24th episode of CBS’ How I Met Your Mother? Well, we hear that Alicia dropped out of her Mother appearance over an intense dislike for Spears that’s spanned nearly a decade.

According to Star Magazine:

“Alicia has disliked the back-on-track pop star for nearly a decade-ever since she tried to get backstage at a 1999 Baby One More Time concert….Britney had her security toss Alicia and her friends out. Alicia was totally embarrassed and she still gets mad when she remembers. There is no way she would work with Britney.”

Britney Spears’ upcoming guest spot on the sinking CBS sitcom How I Met Your Mother has sent Clueless star Alicia Silverstone ducking for cover. Alicia has dropped out of a scheduled appearance on the fourteenth episode of the series after refusing to star alongside Spear and her assortment of shaggy hair extensions.

“Alicia was really excited about appearing on the show, but when she found out she would have to share the spotlight with Britney she wasn’t too keen.”

“She knows that everyone would be going out of their way to look after Britney, and it would be so chaotic nobody would look after her,” a celebrity snitch spills to E!

Alicia will be replaced by Scrubs star Sarah Chalke in the episode, in which Britney plays “sweet and nerdy” secretary Abby.