The couple, who married the day after the boy band split in 2001, already have two sons - Brennan and Kavan - and will welcome their babies into the world in the new year.
Taking to Twitter this morning (8 September), Scott, 33, told fans: "Absolutely over the moon to announce me and my beautiful wife Kerry are expecting twins in January :)"
He also told The Daily Star Sunday that their babies were conceived during 'The Big Reunion Tour', adding: "We've got to get a seven seater car and might have to move house but we're over the moon!"
Liberty X star and Reveal's 'Big Reunion On Tour' blogger Jessica Taylor was quick to congratulate the couple: "Fantastic news guys, congratulations," she tweeted.
The Big Reunion's official account added: "Amazing news, we're absolutely delighted for you both."
Scott and Kerry have also been inundated with messages from fans. Scott has since tweeted: "I would like to thank everyone for their tweets about the twins, me, Kerry and the boys are so excited. Cannot wait to see them #blessed."
See who else is expecting in our gallery below:
Copyright: Vimeo / Weiss Eubanks