Gloria Hunniford and Gethin Jones will also be stepping in when regular hosts Adrian Chiles and Christine Bleakley take a well-earned break later this month.
Gloria and Gethin will fill in from Monday August 17 to Friday August 21. They will be followed by Myleene and John from Monday August 24 to Friday August 28.
The BBC also announced that the popular weekly magazine show – watched by an average audience of 4.4 million – is being extended to include an hour-long show every week from September to the end of the year.
Tessa Finch, executive producer of The One Show, said: “We’re delighted to welcome four One Show favourites to stand in for Christine and Adrian while they’re on holiday.
“The One Show has had a great summer and is gearing up for the autumn season with a brilliant line up of stories from all around the UK and some extremely exciting projects for viewers to get involved with.”
Tessa added: “The new hour long programmes are a great vote of confidence from the audience and the channel. Everyone on The One Show is looking forward to the challenge.”