Bridezilla! Sofia Vergara Driving Joe Manganiello 'Absolutely Nuts' Over Upcoming Wedding -- Find Out Why

Modern Family star Sofia Vergara is causing a major meltdown for her fiancé Joe Manganiello, a source close to the couple tells RadarOnline.com exclusively.

"Joe is so on edge lately and is telling his friends that this wedding is driving him absolutely nuts," says a source.

"Joe loves Sofia very much, but says that she is turning into a complete nightmare and he cannot wait until this wedding is over."

As RadarOnline.com previously reported, the couple plans to say their "I Dos" at The Breakers Palm Beach Resort in South Florida on Nov. 22 – just a few days before Thanksgiving.

"It is supposed to be a joyous occasion, but it is causing Joe more stress than anything else right now," says the source.

Although Vergara, 43, has enlisted celebrity wedding planner Mindy Weiss to take care of most of the details, the source insists that "both Joe and Sofia are very hands-on when it comes to planning this wedding."

However, "they are also on different sides of the fence when it comes to many aspects, including alcohol," the insider says.

"All of Joe's friends are sober and he is warning them that there is going to be a lot of drinking at the wedding because Sofia's family and friends loves to booze."

Vergara herself seems to know she's stepping into Bridezilla territory.

"I am very detail-oriented so I am kind of like a nightmare," Vergara admitted recently. "I have a very good memory. If you show me swatches of things, I can in two months exactly remember, 'What happened with the one with the little border that had the little print?' I'm like, really bad."