Although the network refused to comment on Tennant's status, Catherine Tate told a Radio 2 interview the next season of "Doctor Who" would be her last and may be Tennant's as well, BBC News reported on its Web site.
Tate debuted last year as a runaway bride transported to the spaceship Tardis on Christmas Eve. Tate is to return as the doctor's assistant for the entire run of the upcoming series, which will include an appearance by Freema Agyeman in the role of the doctor's former companion.
Pop star Kylie Minogue is to appear on this year's "Doctor Who" Christmas Day special on the BBC. The "Doctor Who" Christmas show drew an audience of 9.4 million last year.