The singer – who finished runner-up to Little Mix on the eighth series of the talent contest – has been tipped to enter the CBB compound next month.
According to Daily Star, the Liverpool-born singer was called in as a replacement for another celebrity who pulled out of the show last minute.
Ooh, we wonder who?!
Since leaving X Factor, Marcus has gone on to release a self titled studio album, which included his cover of the White Stripes song 'Seven Nation Army'.
The 26-year-old has also appeared in a UK tour of musical Hairspray.
Marcus is dating Strictly Come Dancing professional Robin Windsor.
As always, bosses at CBB won't confirm the celebrity lineup until the show premieres on Wednesday, 7 January, but other rumoured names include Katie Hopkins, Calum Best and US gossip blogger Perez Hilton.
Another former X Factor contestant, Jake Quickenden, has denied rumours he will appear.
Former winner Rylan Clark - who now presents on the show - recently gave Reveal his advice for the new housemates.
"Be yourself. There's no f****** hiding in that house, there's cameras everywhere! And, don't walk out of there and blame the edit!
"We can only edit what you say or do, so what you say or do decides what we can show. If you say a throwaway comment and get picked up on it, well you said it, we didn't put the words into your mouth! Be prepared because everything you say and everything you do WILL be shown. Do not think it won't be!"
CBB premieres Wednesday, 7 January on Channel 5.
Reveal's dream CBB lineup in pictures!
Copyright: Rex Features
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