Fitness star Kayla Itsines announces pregnancy

Kayla annouced her pregnancy today on Instagram. Photo / Instagram

Christmas has come early for Adelaide-based fitness blogger Kayla Itsines.

Taking to social media, Ms Itsines and her partner Tobi Pearce announced they will be expecting their first child.

"Tobi and I do not even have words to describe how happy and excited we are to bring you this news," the 27-year-old wrote alongside the video, which revealed she's 20 weeks pregnant.

"If you don't know already, I come from a big Greek family. FAMILY is always what comes first in my life. To be able to start my own family with the person I love most in this world is just an absolute dream come true."

The video, which showed the pair during an ultrasound, has been viewed more than 1.6 million times in the past hour, and received over 8000 comments.

View this post on Instagram

💛🤰🏻20 WEEKS PREGNANT👼🏻💛 . Tobi and I do not even have words to describe how happy and excited we are to bring you this news!😍 If you don’t know already, I come from a big greek family🇬🇷. FAMILY is always what comes first in my life. To be able to start my own family with the person I love most in this world is just an absolute dream come true. @tobi_pearce has been SO supportive, SO EXCITED and so loving! 😍 He comes home every day, hugs and kisses my stomach. He lays on my legs and asks the baby how it’s day was. He is at every scan and every appointment. I couldn’t ask for a better partner. Our family, well haha.. you can just imagine - they are of course ABSOLUTELY OVER THE MOON EXCITED. I know you are already picturing the look on their faces when we told them😍 I know you ladies probably have 1 million questions ... but for now, let’s celebrate this amazing moment together as we are adding one new #bbg member in May next year. ❤️ We are SO happy to share this news and our journey with you! Thank you everyone !! Tobi and Kayla ❤️ song - Lukas Graham - Love someone @idocinema

A post shared by KAYLA ITSINES (@kayla_itsines) on Dec 19, 2018 at 11:15am PST

"@tobi_pearce has been SO supportive, SO EXCITED and so loving! He comes home every day, hugs and kisses my stomach," she wrote of her partner.

"He lays on my legs and asks the baby how its day was. He is at every scan and every appointment. I couldn't ask for a better partner."

Some of her 10 million followers commented on her post, congratulating the couple on the exciting news.

"Congratulations you guys! This is so beautiful," one person wrote.

"This is the best news ever! Congratulations!," another said.

Earlier this year, the pair announced their engagement by showing off a sparkling ring on Instagram.

View this post on Instagram

❤️We have lived together for over 4 years, we have 2 beautiful dogs, an amazing business....and to top it off...☺️ Tobi got down on one knee last week and asked me to marry him.... in front of my family!❤️ I obviously said YES to spending the rest of my life with my very best friend. We have been together for 5 and a half years now, and I cannot wait for the many years and memories to come .... ❤️💍 I love you so much @tobi_pearce

A post shared by KAYLA ITSINES (@kayla_itsines) on Apr 16, 2018 at 1:31pm PDT

"It was during a family dinner which included some close friends, and I really wasn't expecting it so my reaction was of total shock and happiness," she said. "It was really romantic as Tobi was on one knee.

"We have lived together for over four years, we have two beautiful dogs, an amazing business … and to top it off … Tobi got down on one knee last week and asked me to marry him … in front of my family!," she wrote on social media.

"I obviously said YES to spending the rest of my life with my very best friend. We have been together for five-and-a-half years now, and I cannot wait for the many years and memories to come … I love you so much."

View this post on Instagram

4:45am Monday! I’m wide awake after having slept for almost 12 hours straight because of a head cold! I don’t want to jinx myself but I actually feel completely fine now haha! I think my body just needed a BIG SLEEP!! 💤💤 I think I might try and get out of bed VERY quietly and go walk on the treadmill 😁😁 For the ladies asking what I do when I feel sick, I REST! To get BACK into training after, I walk on the treadmill for 2 days before starting again. Your body needs to rest and recover ladies, let it! www.kaylaitsines.com/app

A post shared by KAYLA ITSINES (@kayla_itsines) on Dec 16, 2018 at 10:18am PST

In October, Itsines was announced as the richest young woman in the country.

Along with her fiance, the pair came in at fifth and sixth place in the 2018 Financial Review Young Rich list, thanks to their staggering combined wealth of $486 million.

Ms Itsines, 27, is now officially Australia's richest young woman, and the couple are the wealthiest self-made 20-somethings in the country.