Confirming speculation, Elisabeth Sladen will resume her role as Sarah Jane Smith, assistant to both Jon Pertwee and Tom Baker.
Buffy star Anthony Head and Coyote Ugly's Adam Garcia will make guest appearances in series two while Penelope Wilton will return as Harriet Jones for the Christmas special.
"We were delighted and honoured by the first series' success, and we can promise new thrills, new laughs, new heartbreak, and some terrifying new aliens," said exec producer Russell T Davies. "The Doctor and Rose are destined to meet Queen Victoria, an evil race of Cat Women, and the dreaded Cybermen. 2006 is going to be scarier than ever!"
Also revealed is the Doctor's new look, described as "geek chic" by new Time Lord David Tennant.
Billie Piper, reprising her role as Rose Tyler for the full series, added: "Wait until you get a load of the new doctor!"