The 43-year-old will begin presenting the show with Phillip Schofield from Monday 22 September as Holly awaits the arrival of her third child.
Following mum-to-be Holly's emotional last day on Friday, ITV have released a series of photographs of Amanda and Phil as they get ready for their first four days of presenting.
Amanda will present the show alongside Phil Schofield
Husband-and-wife duo Eamonn Holmes and Ruth Langsford will continue to present the programme on Fridays.
The news that Britain's Got Talent judge Amanda would take over from Holly was announced in July.
At the time, mother-of-two Amanda said she was already raring to get started on her new project.
"I'm over the moon to get the chance to present one of my favourite shows on TV," she said. "I'm thrilled to be keeping Holly's seat on the sofa warm when she goes off on maternity leave.
Holly shed a tear as she bid farewell to This Morning on Thursday
"I have always been a huge fan of This Morning and love presenting with Phillip so I really can't wait to get started."
Phil, who has been presenting the daytime show since 2002, was equally as keen to see Amanda join him in the studio.
"Really looking forward to working with lovely @Amanda_Holden again," he tweeted. "And then gorgeous @clbleakley steps in to play for the rest of it. How lucky am I to work with the best ladies on telly."