Alicia Silverstone by Jordan Strauss/ WireImage.com, Sarah Chalke by Justin Lubin/NBC Universal Photo Alicia Silverstone by Jordan Strauss/ WireImage.com, Sarah Chalke by Justin Lubin/NBC Universal Photo

Britney Spears' havoc-wreaking cameo on How I Met Your Mother has already claimed its first victim. A Mother insider confirms that Alicia Silverstone - who was slated to appear in a multi-episode arc as Ted's dermatologist/lover - has dropped out and will be replaced by Scrubs' Sarah Chalke.

Pink Is the New Blog reports that Silverstone bowed out because her reps (understandably) feared she would be overshadowed by Spears, who, per my sources, will play an assistant to the dermatologist now being portrayed by Chalke. As a result, I'm hearing Mother bosses Carter Bays and Craig Thomas have reconceived the female doc character. Originally slated to appear in multiple episodes, she'll now be in just one - mostly because that's all Chalke's schedule will allow. The diminished screen time would also seem to eliminate any hope there was of her being Ted's future yellow-umbrella-carrying wife (aka the "Mother").

But Mother still has big plans for Silverstone. "[Bays and Thomas] love Alicia," whispers my mole, "and they intend to create another character for her."

All of this begs a critical question: Is Spears worth the headache? Provided she brings in enough viewers to get Mother off CBS' endangered list, I reckon she is!

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" Britney Is Bonkers for How I Met Your Mother's Ted!
" Britney Spears Lands One Mother of a TV Role