Here comes the bride!

After an 18-month engagement, Ashley Hebert will finally say her "I dos" when marrying her Bachelorette pick J.P. Rosenbaum this weekend.

"This is going to sound pretty cheesy, but we are pretty compatible," Hebert, 28, told Us earlier this year of her bond with construction manager Rosenbaum, 35, who presented her with a 3.5-carat cushion cut Neil Lane diamond when proposing in Fiji during The Bachelorette's May 2011 finale.

Rosenbaum agrees that the couple's chemistry is undeniable. "Whenever we're around each other, it's just easy and comfortable and fun," Rosenbaum said on The Bachelorette. "It's a chemistry you can't ignore; it's just there. I can't be without her. I don't want to picture a life without her. I am more confident with the direction this relationship is heading than I've ever been."

The lovebirds will tie the knot Dec. 1 in a Los Angeles ceremony taped to air as part of an ABC wedding special on Dec. 16.

"Ashley can't wait for people to see [her gown]!" and insider said of the anxious bride-to-be, who said goodbye to her life as a single woman with a bachelorette bash in Scottsdale, Ariz. the weekend of Nov. 17. "The girls had quite the party!" the source revealed. "They had a stripper for Ashley and everyone got spa treatments.