Cedric comes by and Phineas questions him on his first comedy act.

Emma Roberts sat down to chat and even dished out some advice to Isabella on guys!

Randy tells the boys about what dogs they would be and gives Candace some useful singing tips!

Phineas and Ferb welcome star of stage and screen, Neil Patrick Harris.

Who knew Regis loves hip hop and "Squirrels in my Pants"?

Phineas and Ferb rock out with pop sensation Taylor Swift.

Phineas and Ferb spend time with legendary skateboarder Tony Hawk.

Phineas and Ferb get to know the real Seth Rogen.

Actor/comedian Andy Samberg shares some family secrets with Phineas and Ferb!

Jack Black proves he's larger than life as he breaks out the guitar for an impromptu jam session.