It turns out the answer is: A big grin and a bold print!
Coleman will join the cast after Karen Gillan (Amy Pond) and Arthur Darvill (Rory Williams), the Doctor's current companions, exit the series later this year in a "heartbreaking end" after a last encounter with the weeping angels. Her debut appearance will come during the show's 2012 Christmas special.
Her previous acting credits include stints on Emmerdale and Waterloo Road and you can also see her on screen later this year as Annie Desmond in Julian Fellowes' series, Titanic.
So what do you think? Suitable companion material? Suitable outfit choice?
We're just going to come right out and say it: We're going to really miss Karen Gillan but Jenna Louise Coleman looks adorable. Utterly adorable.