Emigrate! Emigrate! Dr's US trip

DOCTOR Who is filming two of next year's four specials in AMERICA-in a move that will boost David Tennant's career Stateside.

The shows will be the 37-year-old star's last, then the Doc will regenerate into another actor.

Viewers will see David arrive in the US to save the world with a BIG-NAME American female assistant.

Series chiefs are also planning a Doctor Who movie-but it is not known who will be the lead.

A BBC source said: "Doctor Who already has a huge following in the States. It's on the Sci Fi channel and is watched by millions of people there every week.

"But two specials in America, with a US setting and a US assistant, will take it to another level. David Tennant is already gaining a huge following and this will make him really hot property." The four specials will also be the final episodes for show boss Russell T Davies.

He is handing the reins to producer Stephen Moffat for the next series, in 2010. The insider added: "Russell is determined to go out with a bang and the specials will be explosive.

"We're spending much more money on them than normal."

Moffat is working on a Doctor Who film-and would love to get legendary director Steven Spielberg involved.

He said: "It would be great to see it in the cinemas-as long as it doesn't get in the way of the show."