Trust David Tennant to make your day.

The Doctor Who star did just that for one couple, who tasked the Tenth Time Lord with revealing the sex of their expected baby.

During a meet in New Orleans, the pair posed with Tennant and handed him an envelope, declaring: "It has the sex of our baby in. We don't know…"

"You don't know?!" the actor answered in disbelief, before the mother asked him to say "allons-y" if it was a boy, and "bad wolf" if it was a girl.

An excited Tennant then took a step back to open the envelope, before shouting his iconic catchphrase: "Allons-y!"

What a delight, eh? We certainly hope they name their boy David after that!

BBC

Meanwhile, Tennant recently reflected on playing the Doctor as he reprised the role for a series of audio plays, insisting that the show will always be a part of his life.

"I always feel fond towards it," he said. "I always feel like it's a happy place to be. It's always a very fond thing to return to, the world of Doctor Who. It's always very welcoming, and friendly, and familiar.

"I suppose I don't feel detached enough from it to feel sentimental, really. Maybe if I'd been completely banished from it for 10 years? But of course it never quite goes away, does it?

BBC

"There's no escaping it, nor would I want to, really. Because Doctor Who sort of runs through my life like a stick of rock. It's sort of always bubbling under, and you know it always will."

The star played the Tenth Doctor between 2005 and 2010, and returned for a one-off appearance in Doctor Who's 50th anniversary special in 2013.

Want up-to-the-minute entertainment news and features? Just hit 'Like' on our Digital Spy Facebook page and 'Follow' on our @digitalspy Twitter account and you're all set.