Stargate SG-1 star Amanda Tapping will join the cast of SCI FI Channel's spinoff series Stargate Atlantis in that show's upcoming fourth season, which commences in the fall, SCI FI announced. Tapping will reprise the role of Lt. Col. Samantha Carter in Atlantis; she played the character in the 10 seasons of SG-1, which goes off the air after completing the final 10 episodes of the current 10th season, starting in April.

Atlantis will resume production on the fourth season in Vancouver, Canada, starting next month. Tapping will appear in 14 of Atlantis's 20 episodes. The new season will introduce a powerful new race, new cast members and mark the loss of beloved friends.

Meanwhile, Jewel Staite returns to Atlantis and will appear in eight episodes, reprising her role as Dr. Keller, a physician who joins the Atlantis expedition. Staite previously appeared on the series as Ellia, the Wraith child who was transformed into a human in the season two episode, Instinct.

Season four of Stargate Atlantis will be executive-produced by Brad Wright, Robert C. Cooper, Joseph Mallozzi and Paul Mullie. Mallozzi and Mullie will share the reins as the series' show runners.

The final episodes of Stargate SG-1 and the remainder of the third season of Stargate Atlantis: Season 2 will air starting April 13, leading into the series debut of Painkiller Jane.