Jessica Steen played Dr. Elizabeth Weir in the episodes Lost City, Part 1 and Lost City, Part 2. Steen was replaced by Torri Higginson after SG-1's seventh season. When asked about this decision, Steen replied on her web site with the following quote:
“We don't know why. When Jessica was hired for the two part Season Seven finale' (Lost City) she was told that her character might be in a possible Stargate spinoff series. Jessica was even paid not to take any other work until it was decided if they were going to do the spinoff. Stargate: Atlantis was eventually given the green light, but for whatever reason, "the powers that be" decided to go with another actress.”
Ironically according to the same official website front page "Her television appearances include...Stargate Atlantis...".
She is also known for playing Special Agent Paula Cassidy on NCIS and Corporal Jennifer 'Pilot' Chase on Captain Power and the Soldiers of the Future.