The couple will be tying the knot at the end of this month in Italy, reported People magazine.
"George has chosen and been fitted for an Armani suit for his wedding," Armani said during an appearance at Emporio Armani show at Milan Fashion Week.
So far there is no confirmation regarding the bride-to-be's gown. However, she was spotted at the London headquarters of Alexander McQueen alongside her mother earlier this month.
The 'Gravity' star and the human rights lawyer's wedding reportedly will include some tequila as a part of the feast.
Their nuptials would include his 'Ocean's Eleven' co-star Matt Damon, Sandra Bullock, Brad Pitt, Angelina Jolie, Bono and Ellen Barkin. The guests reportedly will stay at Hotel Aman.