It sure didn't take long for Alicia Silverstone to look like small potatoes. A CBS rep officially confirms for TVGuide.com that which was reported an hour ago on Pink Is the New Blog: Britney Spears is guest-starring on an upcoming episode of How I Met Your Mother. TMZ says it's by no means a long-term gig and that her dad/conservator signed off on it. (Jamie however simply had to draw the line at a similar offer from Welcome to the Captain.)

At this time, no details are being made available as to when Spears will tape her appearance or when it will air, but unreliable sources tell me Barney will have cause to coin the new catchphrase, "Thong up!"

http://community.tvguide.com/blog-entry/TVGuide-News-Blog/Todays-News/Britney-Spears-Lands/800035278

this sounds interesting. I hope Britney will do a good job