Amanda Tapping, Richard Dean Anderson Amanda Tapping, Richard Dean Anderson

Stargate SG-1 and Atlantis fans have cause to be over the moon.

Sci Fi has opened up the Stargate vault of characters and announced several past favorites will guest-star on Stargate Universe throughout its freshman season.

Most notably, Richard Dean Anderson and Amanda Tapping will reprise their roles as General O'Neil and Colonel Carter, respectively. Fans will also be treated to guest spots by Stargate alums Michael Shanks (Dr. Jackson) and Gary Jones (Chief Mst. Sgt. Harriman) as well.

Other notable guest stars:

-Christopher McDonald (Superhero Movie) will play Senator Armstrong, who heads a committee that governs the Stargate program.

-Carlo Rota (24) will star as Carl Strom, the head of the civilian oversight committee that heads up the Atlantis Expedition.

-Janelle Monáe, the Grammy-nominated artist, will play herself and will perform "Many Moons" and "Sincerely" from her latest album.

Stargate Universe is the third series in the Stargate franchise, starring Robert Carlyle, Lou Diamond Phillips and Ming-Na, and is set to premiere in October of 2009.

Which guest star are you most excited to see?