It has not been revealed yet whether the X Factor twins will be performing their debut solo single 'Under Pressure (Ice Ice Baby)'.
"Bringing their unique Irish charm to the show, they'll be sharing their views on the celebrity housemates with Davina on Big Brother's Big Mouth." said a show spokesperson. Comedian Jarred Christmas has also been confirmed as a guest.
The Grimes brothers have appeared with George Lamb on Big Brother's Little Brother during the week.
Big Brother's Big Mouth airs on Friday at 11pm on Channel 4.