Phillips, who quit GMTV in 2008, is among the presenters who will host the slot when Kelly takes her summer break, reports the Mirror.
The 49-year-old said that she was looking forward to making her return.
"I've spent nearly a third of my life so far sitting on the GMTV sofa, so I'm really excited to be going back to see my old mates and the viewers again," she said.
Emma Bunton and Kirsty Gallacher will also guest-host the show.
Don't Stop Believing host Bunton said: "It's great to be asked back again to Lorraine's sofa. I can't wait to see what we'll get up to this time and what fabulous guests are being lined up to join me".