Peta Murgatroyd and Maksim Chmerkovskiy are "beyond happy" to be expecting another baby boy

In a video, in which the family dressed in black with giant balloons around them, Peta, Maksim and their children found out the happy news by cutting into a cake filled with blue sprinkles and launching blue powder.

Alongside the video, Peta wrote on Instagram: "It's a .......BOY! [blue heart emojis].

"I've been quietly preparing myself to be a real-life wolf pack Mumma with our THIRD baby boy on the way [prayer, cry-laughing and blue heart emojis] I CANNOT BELIEVE WE WILL HAVE 3 BOYS!! [six cry laughing faces]!

"Maks and I are beyond happy to have another buddy for Shai and Rio...we want them to be the best of friends and thinking about family dinners already makes us laugh!

"Not to mention when Rio turns 1 , I will give birth to this bundle of joy a couple of weeks later [dancer emojis] LET THE GAMES BEGIN ....(sic)"

Maksim, 44, previously insisted he wasn't bothered if he had another son or his first daughter.

Asked if he wants to have a girl or a boy, he told Us Weekly magazine: "I want ten toes, ten fingers and a beautiful smile.

"I'm good 100 per cent regardless."

Meanwhile, Peta, 37, admitted having another baby had been a "surprise".

Announcing her pregnancy, she wrote on Instagram last month: "We Are Having A Baby [celebration emojis]

"Yes we know...we just had a baby... haha! This was very unexpected at (4 months postpartum with Rio) but we are sooooo happy and so ready to be a family of 5 soon! (sic)"

But she also hailed the news as a "miracle" after previous struggles to get pregnant.

She wrote: "After everything we've been through with miscarriages and IVF we're beyond blessed and know we are uber lucky for this miracle to happen to us. We're just so happy that we can finally tell you guys the good news [tears emoji] (sic)"