She is married to Dr Jeremy Norton; the couple have two children. The actor David Tennant is a close friend and is godfather to her youngest child. When Tennant first moved to London in the early 1990s, he lodged with Weir at her house in Crouch End for five years; they had met on the set of the BBC Television series Takin' Over the Asylum.
In 2001 Weir took part in the Weakest Link Comedians Special.
Weir appeared in the Doctor Who 2011 Christmas Special 2011 "The Doctor, the Widow and the Wardrobe".
From 2013 until 2016 she starred as Jenny in Drifters.
In 2015 she joined the team of presenters for BBC Two's Food and Drink programme.
Since 2016, she has starred in the BBC sitcom Two Doors Down. Weir's performance was criticised by Ben Arnold, writing in The Guardian, who commented "her Scottish accent [is] still a work in progress, it would seem."
