The pair tied the knot in front of 120 family and friends at Babington House in Bath.
Millie wore a gorgeous vintage lace dress complete with long veil and white Louboutin heels, which she matched with a floral headpiece and a bouquet of pink and white roses.
The 23-year-old Quality Street heiress arrived at the church on the arm of her father, Nigel.
Professor Green - real name Stephen Manderson - ditched his usual jeans and hoodie combo for a smart blue suit.
He took to Twitter on Monday to confirm that he and Millie would be walking down the aisle on Wednesday.
"Thank you all for your kind wishes, as you may have read I'm marrying the love of my life tomorrow so I'm off for a little while, big love x," he wrote.
The guest list included Lily Allen and her hubby Sam Cooper, Miquita Oliver, Miles Kane and Example.
And despite Pro Green saying he was banning any 'Made In Chelsea' stars from attending, Caggie Dunlop and Rosie Fortescue still managed to get an invite.