And last month, Hearst shared a photo of Hardwick's tuxedo-fitting in Beverly Hills.
"You are the best thing that has happened to this world, in my eyes," Hearst wrote. "You are truly one of a kind @Hardwick. In exactly one month from now, I will be walking down the aisle, and we will be husband and wife. You are a constant source of inspiration and give me reason to strive for more of everything. With you, my heart has finally found a home, and my heart is forever yours. I just love EVERYTHING about you, and cannot wait to spend the rest of my life with you!!!"
"My biggest win of the night was actually @lydiahearst saying YES!!!!" Hardwick wrote along with a photo of the engagement ring. "This ring belonged to her grandmother Catherine Hearst and @patriciahearst has graciously and wonderfully passed it down to me to give to Lydia. IT'S OFFICIAL!!! What an absolutely perfect and amazing night!! I love this woman with all my heart....#YesThisMeansWhatYouThinkItMeans."