Parents-to-be Ashton Kutcher and Mila Kunis got a practice run at walking down the aisle last week in Louisiana.

The engaged twosome, who’s also planning their own nuptials, acted as witnesses at Kutcher's sister’s wedding during their week-long visit to the quaint town of Slidell just outside of the Big Easy, Breaking Celebrity News has learned exclusively.

Tausha Kutcher, who is also pregnant, and her new husband, Ken Kordisch, along with the actor, Kunis, and the actor’s niece Dakota looked on in the gorgeous gardens of Woodridge Bed & Breakfast in Pearl River as they said their “I dos.”

“It was a thrill. Quite a surprise!” gushed owner Debbie Fotsch.

“We knew that a couple was getting married and we knew the last name. I sort of in my mind teased around asking if her brother was Ashton. But I didn’t. What are the odds! They walked up to the door and we opened it up to people we only see on TV.”

The elopement festivities on April 16 were a casual affair, with the bride dressed in a short white dress, as her brother donned khakis and a white shirt and her future sister-in-law Mila covering up her baby bump in a long black skirt and a jean jacket.