There are a few tried and tested ways a celebrity can reveal they are expecting to the world.

They can go the old fashioned route and share a grainy ultrasound snap on Instagram. They can use a clever pun – à La Megan Gale – and share a snap of a cute bun roasting in an oven.

They can pull a Beyoncé and share an image of a bump the world somehow failed to notice for months.

All are great. All are guaranteed to make headlines around the world.

But none of those are as cute as the pregnancy announcement model and TV presenter Chrissy Teigen just shared.

Chrissy and her musician husband, John Legend, let their one-year-old daughter, Luna, announce the happy news to more than 15 million people on social media.

“Luna, what’s in here?” 31-year-old Chrissy can be heard asking her daughter, pointing to her stomach.

“Baby!” she replies.

it’s john’s!

A post shared by chrissy teigen (@chrissyteigen) on Nov 21, 2017 at 1:15pm PST

The model managed to ensure her unique sense of humour made it’s way into the announcement too, captioning the adorable video, “It’s Johns!”

The couple have spoken honestly and openly about their struggles with falling pregnant, and how IVF helped them welcome Luna into the world.

LISTEN: Is a fear of vaginal birth a good enough reason to have a caesarean? We ask Midwife Cath.

“Having a baby is a big challenge for a couple, and going through that together strengthens your bond because if you make it through [having a child], you know you can make it through anything,” John Legend told Cosmopolitan magazine in August.

“We’re lucky that we’re living in an age where we can conceive in other ways. [IVF treatment] brought us Luna and hopefully it will bring us a few more awesome kids, too.”

In March, Chrissy revealed she had been battling postpartum depression since the birth of Luna in April 2016.

“To a lot of you, I think, I seem like the happiest person on the planet,” she wrote in a raw and emotional essay for the April issue of Glamour magazine, admitting that for most of last year, she felt incredibly unhappy.

“I had everything I needed to be happy… How can I feel this way when everything is so great?” she said.

“I’ve had a hard time coming to terms with that, and I hesitated to even talk about this, as everything becomes such a ‘thing’. But it’s such a major part of my life and so, so many other women’s lives.”

It wasn’t until a GP diagnosed her with postpartum depression and anxiety that she began to make sense of what she had been feeling.

Last day. My love.

A post shared by chrissy teigen (@chrissyteigen) on Mar 22, 2017 at 9:52am PDT

“I remember being so exhausted but happy to know that we could finally get on the path of getting better,” she wrote.

“I started taking an antidepressant, which helped. And I started sharing the news with friends and family – I felt like everyone deserved an explanation, and I didn’t know how else to say it other than the only way I know: just saying it.”

Listen to the latest episode of Mamamia’s pregnancy podcast, Hello Bump: