Punters may be praying for a winner during the day but will be Living on a Prayer later that night as Epsom Day adds Bon Jovi's former guitarist to the bill.

Richie Sambora will play Randwick after the final race on October 1 alongside Australian singer Orianthi, under the stage name RSO.

Epsom Day is the major event in the spring carnival with three Group One races, including the $1 million Epsom Handicap.

"From what I hear, the atmosphere will be electric, Orianthi and I can't wait to add a bit of magic to what will already be an impressive day," Sambora said.

The pair will take centre stage in the Theatre of the Horse behind the main grandstand.