The music mogul will watch the final performances on The X Factor via Skype before talking to the judges in the first part of The Xtra Factor.
The Syco boss left the show last year and is yet to appear on this year's live shows due to commitments to Fox's X Factor USA series. He remains a producer of the ITV1 programme.
Cowell will be projected onto a screen at the back of the stage, which is reportedly the largest in Europe.
This weekend's X Factor final will feature contestants Marcus Collins, Amelia Lily and Little Mix as they fight for the chance to win a recording contract with Cowell's Syco and a Christmas single.
Cowell has spoken to the contestants via Skype, offering advice and comments on their performances.
The X Factor final will begin at 8pm on Saturday on ITV1.
Watch yesterday's X Factor finalists' press conference in full below: