Former Beverly Hills , 90210 actress Shannen Doherty was cast as the eldest sister Prue Halliwell , while her best friend and former Picket Fences actress Holly Marie Combs played the role of the middle sister Piper Halliwell . Lori Rom was originally cast as the youngest sister Phoebe Halliwell in the 28 - minute unaired pilot episode . However , Rom quit the series , and a new pilot was filmed with former Who 's the Boss actress Alyssa Milano in the role of Phoebe . Doherty departed Charmed at the end of the third season and was replaced in the fourth season by film actress Rose McGowan , who played the long - lost younger half - sister Paige Matthews .

Question: who was originally cast as phoebe on charmed
Answer: Lori Rom