The glamour model and bodybuilder, who took part in the 2006 series, will set the housemates a series physical challenges in a fitness task, according to The Sun.
The group will be divided into two groups, with the winning team receiving a prize from celebrity chef Aldo Zilli over the weekend.
© Yui Mok/PA Wire/Press Association Images
Marsh hinted on Twitter yesterday that she would be entering the house, telling fans to "keep watching".
Celebrity Big Brother returned to Channel 5 on Thursday with 3.5m viewers.
The housemates won their first task yesterday (January 6), securing Romeo's suitcase in 'Celebrity Circuit'.
