As has become customary recently, this year’s Children in Need event will include a teaser clip from the 2017 Christmas special.
The line-up of hosts for the charity appeal was revealed, and included this beautiful li’l sentence:

“There is also a sneak peek at the Doctor Who Christmas special.”

No exact time will be announced, but it will take place in the first segment of the show, which begins at 7:30pm and runs for 2 hours 30 minutes. This will air on Friday 17th November 2017 on BBC1.
By the time Children in Need night rolls around, we’ll be a little over 5 weeks until Twice Upon A Time, the festive episode that’s expected to air on Christmas Day, which means all the little boys and girls all over the land will be getting excited for a visit from Saint Nick the Doctor Who special. But it will, of course, be the last regular appearance of Peter Capaldi as the Twelfth Doctor. He’ll be joined by David Bradley as the First Doctor, as teased in the cliffhanger to The Doctor Falls, the finale to Series 10. It will also be the last episode written by Steven Moffat as showrunner.
Doctor Who has a long history with Children in Need – notably, for many, we were treated to special “minisodes”, including David Tennant’s first full scene as the Tenth Doctor back in 2005, often acting as preludes to the Christmas special – but recently, we’ve instead seen clips from the festivities. Last year’s, for instance, saw the Doctor eating Sushi, meeting Lucy (Charity Wakefield), and then being saved by the Ghost (Justin Chatwin) – all of which we’d see again in The Return of Doctor Mysterio.
Twice Upon A Time should air on Christmas Day. And don’t forget to donate to Children in Need!