"I had been holding onto my dad, trying not to cry," McPhee told People, adding her father Daniel was "happy" to give her away. "Then the doors opened, and I was blown away."
McPhee and Cokas -- who had been dating for two years before he popped the question last spring -- exchanged "I dos" in-front of 305 guests, however the 42-year-old only noticed his 23-year-old bride.
"Her beauty and the beauty of the moment exceeded anything I could have ever dreamed of," Cokas told People. "It was incredible."
Once the ceremony was over, McPhee and Cokas' wedding reception was held at St. Viviana's, a former cathedral that is currently used for private parties. Cokas then sang Bill Joel's "She's Got a Way" to his new wife, while she sang Natalie Cole's "Unforgettable" for him.
"We're a perfect fit," Cokas told People.
The whole affair was also apparently unforgettable for McPhee's fellow Idol 5 finalist Kellie Pickler, who roomed with the bride during the show's Summer 2006 installment and formed a personal relationship with her.
"I was so honored when Katharine asked me to be a bridesmaid," Pickler told People. "[The day] was so magical. It was like a fairy tale. I didn't want it to end."