TV star Dooley, 35, first met Clifton when they competed on Strictly together in 2018, before taking home the glitterball trophy.
Sharing a picture of her bump on Instagram, she wrote: “Gaaaaaaang… We are having a baby! So bloody delighted.
“Kev, you’re magic, I love youuuu. (Was becoming impossible to hide and if one more person asks me if I’ve had my t*** done in LA I’m gonna scream.)
Clifton, 39, was a professional dancer on Strictly from 2013 to 2019, and won the 16th series with Dooley before announcing they were a couple.
Taking to his own Instagram account, Clifton wrote: “We’re having a baby! And I think my girl @sjdooley looks beautiful pregnant.”
The couple’s celebrity friends were quick to offer their congratulations in the comments section.
Leading the well wishes was former Love Island host Laura Whitmore, who wrote: “So delighted for you guys!! Congrats.”
“SO made up for you,” echoed This Morning presenter Rochelle Humes, while their former Strictly co-star said “Congratulations,” followed by a string of red love heart emojis.
“Ohhhhh thrilled for you guys! Amazing xxxx,” added singer Jessie Ware.