The 22-year-old twins have been approached by Channel 5 to "sex up" the house and serve as a romantic interest for fellow rumoured contestant Kirk Norcross of The Only Way Is Essex, according to The Sun.
"The girls have pledged to really sex up the Big Brother house," a source commented. "Kirk won't know what has hit him. But with his ladies' man reputation, he is sure to be tempted by our Playmates."
The Shannon sisters acted as Hugh Hefner's live-in girlfriends between 2008 and 2010, but were ordered to leave the Playboy mansion when his relationship with ex-fiancee Crystal Harris started to heat up.
They returned to the property shortly after the couple split in June.
Lindsay Lohan, Nicola McLean, Natasha Giggs and X Factor contestant Frankie Cocozza are among the other stars rumoured to be joining Celebrity Big Brother.
Tinchy Stryder and TOWIE favourite Sam Faiers both confirmed this week that they turned down offers to appear on the show.
Celebrity Big Brother returns on January 5 at 9pm on Channel 5.
> Celebrity Big Brother on Channel 5 to bring back partial live feed
Watch a trailer for Celebrity Big Brother below: