Tate has replaced Tennant in the starry Winchester Cathedral line-up, which also includes Broadchurch’s Olivia Colman, Downton Abbey’s Hugh Bonneville and acclaimed actor Timothy West.
The Murray Parish, which organised the event, wrote on their website: “Sadly, one of our celebrity hosts, David Tennant has advised that due to unforeseen circumstances, he is suddenly now unable to be present at our Christmas Celebration on 7th December at Winchester Cathedral.
“David is deeply sorry and disappointed, but is away filming on location and complications have meant that he is unavoidably detained.
“However, David has arranged for his very good friend and former Dr Who Assistant, Catherine Tate, to take his place!
“We hope our guests will understand that these things happen in the world of showbiz and continue to look forward to what will be a truly spectacular evening.”
The Murray Parish Trust is a charity founded by actress Sarah Parish and her husband, actor James Murray, in memory of their late daughter with the aim of providing funds to advance paediatric emergency medicine.
The Winchester Cathedral Christmas Celebration, which will have “both musical and theatrical content” and “an uplifting variety of festive and magical performances” will take place on 7th December 2017.