The Danish tennis star agreed to carry the world number two's clubs for him for the event and tweeted her excitement at the prospect today.
"Excited to be @mcilroyrory 's first ever female caddie today!," she tweeted.
Former world number one Wozniacki is making her first visit to the Masters and McIlroy's delighted he got his girlfriend to carry his golf bag into action on the hilly Par 3 course.
"I just want to get her into one of those white boiler suits the caddies must wear at Augusta," quipped the Ulsterman
Wozniacki invited McIlroy to join her on the tennis court during a break in play at an exhibition match in New York's Madison Square Garden last year and play a point against her opponent Maria Sharapova, which he won.
In keeping with tradition, Wozniacki will be expected to play a shot off the ninth and final tee across an expanse of water.
Many of the golfers including Phil Mickleson and Ernie Els had their children caddy for them in the laid-back event.