She then decided to make it a reality by secretly plotting with her sister's boyfriend to help him propose on her big day "We shared everything growing up... my wedding day was no different," the ...

"I really thought everything was okay until she handed me the mirror," the bride Alexandra Geahlen tells PEOPLE ...

A video of the heartwarming moment went viral on Instagram ...

"There wasn’t a dry eye in the room," bride-to-be Madeline Richter tells PEOPLE of the big reveal ...