Philbin died of natural causes on Friday. He was 88.
"He was the ultimate class act, bringing his laughter and joy into our homes everyday on Live for more than 23 years. We were beyond lucky to have him as a mentor in our careers and aspire everyday to fill his shoes on the show. We send our deepest love and condolences to his family and hope they can find some comfort in knowing he left the world a better place."
Ripa and Philbin co-hosted Live from 2001 until Philbin left in 2011.
"There are no words to fully express the love I have for my precious friend, Regis," Gifford wrote in her own post on Saturday.
"I simply adored him and every day with him was a gift. We spent 15 years together bantering and bickering and laughing ourselves silly -- a tradition and a friendship we shared up to this very day. I smile knowing somewhere in Heaven, at this very moment, he's making someone laugh. It brings me great comfort knowing that he had a personal relationship with his Lord that brought him great peace. I send all the love in my heart to Joy, to his children, to the rest of his family and to the innumerable people he touched over his legendary life. There has never been anyone like him. And there never will be."
Philbin and Gifford worked together 1985 to 2000.