Katharine McPhee is struggling to grapple with her father's death just weeks after she and David Foster happily announced their engagement.

In an Instagram post uploaded early Tuesday (July 17), McPhee confirmed she lost her father, David, who was her consummate cheerleader.

“I can’t believe I’m even writing this,” she began. “But it is with heavy heart that I share that my sweet sweet Papa left this earth yesterday morning. We as a family are completely heartbroken and devastated. He was my biggest fan, my biggest champion, always telling me to ‘Give em hell kid!’”

“He was so kind and caring and made sure we knew how much he loved us. Not sure my heart will ever be the same," she continued. "Not sure my heart will ever be the same. I’m so sad he missed my broadway debut. But when I return to the stage next week I hope he can watch it in peace and from up above. Thank you to all my friends who’ve been so loving and supportive these last 48 hours. I love you Papa. I already miss you so much. This hurts."

And fans shared their condolences in droves.

"I know it's not easy right now but hang in there, I'm sure you have lot of memories. he's not gone he's in you, in your head and everything you do you will NEVER for get him. my condolences to your family!" one wrote, while another noted "love makes it almost unbearable right now, but that same love will also be what brings you joy when you remember him. Be blessed that he was yours and you were his! He’ll undoubtedly be constant, always near when you need him, because your hearts are forever connected!"

Just a few days before David's death, Kat posted a tweet in which she apologized for having to fly to Los Angeles for a "family emergency."