The Doctor is in and he has a new companion.

The Sci Fi Channel has acquired the fourth season of "Doctor Who" and its new spinoff "The Sarah Jane Adventures" from BBC America to premiere in April 2008.

David Tennant will reprise his role as the tenth Timelord for this fourth season of "Doctor Who" and he's joined by Donna Noble, the runaway bride from the Christmas special the previous season played by Catherine Tate. Former companion Martha Jones (Freema Agyeman) will return in the middle of the season.

"Sarah Jane," which is written and produced by the same creative team behind the good doctor, centers on one of the Doctor's previous companions. Her years traveling the universe with him makes her particularly equipped to handle alien encounters, mysteries and dangers with the help of her new young friends Maria, Luke and Clyde.

"We are excited to have 'Doctor Who' back on Sci Fi for its fourth season," said Chris Regina, Vice President of Programming, Sci Fi Channel. "It's an exciting franchise that continues to reinvent itself for new generations of viewers. The youthful appeal of 'The Sarah Jane Adventures' will no doubt attract even younger new viewers."

Candace Carlisle, EVP Sales and Co-productions, BBC Worldwide Americas added, "The imagination of Russell and the rest of the production team in Cardiff who have produced these two incredible shows is outstanding. We are so pleased that the loyal fans of the Sci Fi Channel will be able to meet a whole new range of characters and aliens that are intrinsically linked to the Doctor's history. Both 'Sarah Jane Adventures' and the new season of 'Doctor Who' are jam-packed with some of the most creative storylines ever produced by the BBC's brilliant team."

"Doctor Who" is the longest-running science fiction TV series to date and was revived recently starring Christopher Eccleston ("Heroes") as the ninth incarnation of the Doctor. Tennant replaced him beginning with the second season and has since enjoyed solid viewership with the series on Sci Fi.