Vanderpump shared a throwback photo of herself with Mark at dinner. She added a broken heart emoji in the caption.
"Rest In Peace big brother," the star wrote.
Vanderpump thanked fans for their support in a subsequent post.
"It's been a devastating couple of weeks... one day at a time..." she captioned a photo of herself riding her horse. "I thank you all from the bottom of my heart for all your love and support. Love Lisa xo."
Brittany Cartwright and Tom Sandoval, who work at Vanderpump's restaurant SUR and co-star with her on Vanderpump Rules, were among those to reach out in the comments.
"I'm so sorry Lisa! Sending all my life and prayers to you and your family," Cartwright wrote. "We love you Lisa!"
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"Hang in there Lisa we all love u so much!" Sandoval added.
Mark was found dead April 30 at his home in Gloucestershire, England, according to The Daily Mail. He was 59.
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