Andy Cohen

Alyson Hannigan spills the beans on all things 'Buffy the Vampire Slayer' on 'Plead the Fifth.'

Zachary Quinto and Alyson Hannigan guess whether the fan portraits are 'Sci Fi or Oh My!'

Alyson Hannigan teaches Andy Cohen how to sign an autograph with his foot.

Part I: 98 Degrees talk about their new album and Sweet Brown tries to seduce the Lachey brothers.

Part II: Nick Lachey sounds off on Joe Simpson and 98 Degrees dish on their favorite song.

Sweet Brown delivers a very special Mazel of the Day to Cleveland hero Charles Ramsey.

The guys from 98 Degrees throw some shade at their rival boy bands.

Nick Lachey dishes on when he last saw ex-wife Jessica Simpson.

The guys from 98 Degrees teach Andy how to get sexy for the camera.

Part I: Dr. Simone reveals a secret about Dr. Jackie and Dr. Jackie dishes on the infamous party.

Dr. Jackie & Dr. Simone dish on their friendship, camel toe, and HPV.

Dr. Jackie and Dr. Simone face off in a hilarious game to save "Sandy" Cohen.

Andy Cohen twerks it all over New York in solidarity with the high schoolers who were recently suspended for twerking.