The presenting couple have become parents for the first time.
Love Island's Iain Stirling and Laura Whitmore led the tributes a year on from Caroline's death.
"It’s been hard to keep such happy news quiet," the presenter wrote on Instagram.
Marvin Humes will be on hosting duties for the very special episode of the ITV daytime show.
Love Island's Laura Whitmore and Iain Stirling and Radio 2's Zoe Ball are among those joining the Channel 4 show.
The Love Island host confronted a photographer after she reunited with boyfriend Iain Stirling for first time since Caroline Flack's death.
The episode opened with the show's narrator heartbreakingly saying: "I'm going to miss you, Caz."
Love Island's Laura Whitmore: ‘I Pray Iain Stirling’s Scared Enough Of Me Not To Say Anything He Shouldn’t’
The ITV2 show's new host has a romantic connection of her own to the narrator – and she's hoping to keep him in check.
Maya Jama, Emily Atack and Amber Gill are among the hot favourites to succeed Caroline, who was recently charged with assault.
The ITV2 reality show is returning in the New Year for its first of two series in 2020.