-- Catie Bossard was thrilled when her boyfriend of a year proposed while they were atop a mountain during a visit to Vail, Colorado.
But when, seconds later as the couple's family and friends started running toward them, Zach Baldwin asked Bossard if she wanted to get married that same day, well, she couldn't contain her emotions.
"That was when it kind of hit me," she told ABC News. "I'm like, 'Yes! Yes! Let's do it.'"
The Denver, Colorado, couple's surprise wedding was actually two months in the making. Baldwin, 25, told ABC News that he "got this idea one day having dinner with a co-worker."
"He was joking about having our family all in town and knocking it all out in one day," Baldwin said. "When I thought about it more and more. It just seemed too perfect."
So Baldwin planned that the two would drive from their shared home in Denver to Vail. He then dropped to one knee on the top of a Vail mountain after a scenic gondola ride.
"I can honestly say absolutely everything fell into place as I had envisioned it from the beginning," Baldwin said.
Bossard, 24, recalled that as their family and friends came over to congratulate them, her fiancé had a second question. "He said, 'My second question is do you want to get married today?'"
After the bride-to-be was on board with the whirlwind plan, the two popped open a bottle of champagne and returned to their hotel to prepare for the wedding set for four hours later.
Bossard was thrilled when she found out that her best friends along with her sister and mother had thought of everything -- from her wedding dress and undergarments to her makeup and hair accessories.
Her mother had even brought her great-grandmother's handkerchief, which she tied around the bouquet. She also wore her grandmother's pearls.
As far as decorations, well Mother Nature took care of that.
"It was simple but beautiful," Bossard said. "With the scenery, you don't need much up there. There's no need for any flowers. The entire view of the mountains behind you: that alone takes your breath away."
The couple is now looking forward to their honeymoon. Bossard said they plan to backpack through Costa Rica in November.
For now, they're looking forward to living as husband and wife.
"I am looking forward to experiencing everything life has to offer with Catie," Baldwin said. "She brings a light into every situation that cannot be contained and inspires me everyday to be the best husband I can be."
"He makes me a better person," Bossard said. "I love being around him and I love enjoying life with him, whether its traveling, being at the house, working out. I’m excited to spend my life with him."