Clooney, 53 and Amal are currently putting the final touches on their upcoming wedding which is said to be held on September 27, reported Us magazine.
"It is crazy enough, her family is paying for most of it... It's all very classy," the source said, adding that Amal's sister Tala will be her maid of honor while Clooney's friend, Rande Gerber, will be his best man.
The 'Gravity' actor has only invited 60 guests to his wedding.
Clooney's 'Ocean's Eleven' co-star Matt Damon and his wife Luciana as well as Rande and his wife Cindy Crawford are also being invited.
Opera singer Andrea Bocelli will reportedly perform at the nuptials.
Clooney, who proposed to Amal back in April, declared his love to her during his acceptance speech at Celebrity Fight Night earlier this month.