Tulisa Contostavlos's ex-boyfriend - real name Justin Edwards - is said to have been on Channel 5's wishlist to become a new housemate, according to The Sun.
Edwards caused controversy earlier this year after leaking a sex tape recorded during his relationship with the X Factor judge several years ago.
Tulisa's lawyers reportedly contacted TV bosses informing them that Edwards had signed an agreement not to appear on any reality shows.
An insider said: "Producers wanted Justin to take part in Celebrity Big Brother because of the publicity he would bring."
A spokesman for MC Ultra added: "Reality TV is not his bag and it is not something he would want to do."
MC Ultra originally denied releasing the sex tape, but he later retracted his claim after being taken to court over the leak.
Justin Lee Collins has denied that he may be taking part in the next series of Celebrity Big Brother in January.
In pictures - Celebrity Big Brother 2012 - Rumoured stars: