Having starred as one of Bridget Jones's best friends, performer-writer Sally Phillips here reinvents the tragically single heroine as a Scottish wallflower caught in a media storm way out in the Outer Hebrides.
Adding a nip of Local Hero to equal parts Notting Hill and Made Of Honor, the plot sees Hollywood star Lana Tyler (Eve) and her Hugh Grant-ish fiance James (Tennant) forced to marry in secret to avoid the world's press.
They opt for the fair(ish) isle of Hegg (pop: 75; average age: 75). Unfortunately, their cunning plan is scuppered when Lana spots international super-pap Marco Ballani (Federico Castelluccio, a long way from The Sopranos) lurking in the bushes.
To give Ballani the pics he wants, Lana's agent Steve (Ugly Betty's Michael Urie) offers big money to local lass Katie (MacDonald) to stand in for Lana for a mock ceremony.
A jobbing copywriter who has come home to Hegg after breaking off her engagement, Katie reluctantly accepts – though only so her ailing mother can realise her round-the-world dream.
But as fellow writers, Katie and James should know that - by definition - you can't have a hitch without a hitch. Even a fake one.
While co-written by a veteran of more risque TV fare as Smack The Pony and I'm Alan Partridge (Phillips, who also takes a small role), this romantic mcnugget is less salty than you might expect.
Opting for gentle chuckles over razor-sharp observation, it aims solely to warm the cockles and bring a little parochial colour to your cheeks.
And by giving Tennant and MacDonald a chance to relax after respectively racing around as Doctor Who and propping up Boardwalk Empire, The Decoy Bride pretty much ticks both boxes.
Nobody's forecasting gales of laughter, but it'll give your pipes a canny wee toot.