The veteran TV judge, 67, seems to have seriously slimmed down this winter with the new footage showing a clearly trimmer figure compared to snaps from previous years.
Louis announced in the short video: "Don't forget the X Factor final is this Saurday. You can see it on ITV and STV. Don't forget!"
Lorraine, 59, complimented the Irish music business veteran and asked if he'd had any cosmetic surgery.
She said: "Can I just say you're looking really well Louis? Have you had any work done?"
The X Factor judge and Westlife manager laughed, before insisting: "I haven't had any help in a really long time."
Finalist Megan, 27, then teased: "He did have a spray tan done in Essex though!"
Lorraine continued to probe into Louis' secret weight loss journey as she questioned the Irish TV star.
She added: "You've lost tonnes of weight and you look really really young. it's ridiculous!"
Without giving away his secrets, Louis said his weight loss was down to "loving what I do" and revealed that "the music business keeps me young."
The Irish music mogul may have taken some tips from his TV boss Simon Cowell after his own highly-publicised weight loss journey.
Simon, 60, famously lost more than 20lb in weight and the TV talent judge put it down to him turning to a vegan diet.
Simon changed his lifestyle in October 2017 after he fell down the stairs in the middle of night.
The health scare forced him to change his ways and he has been living a healthier lifestyle ever since.
The three judges are preparing for their big night on Saturday as Celebrity: X Factor ends with it's highly-anticipated final.
The four acts vying for the top spot are Jenny Ryan, Max and Harvey, Megan McKenna, and V5.
One of the acts will win a coveted recording contract with Simon Cowell's Syco Entertainment record label.
*Celebrity: X Factor The Final airs this Saturday on ITV at 7.10pm.
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