Lady Gaga
Credit: lagygaga/Twitter

We are incredibly sad to learn that Lady Gaga's best friend, Sonja Durham, has passed away after a grueling battle with breast cancer.

"She had this incredible way of releasing me from the anchor of my own sadness that held me back, she loved me fearlessly while I learned how to cope with fame and stay inspired no matter how scared I was," the star stated in an Instagram tribute to her friend posted on Sunday. "She knew all I cared about was the music. She made that OK. I'm in shock that I won't see her again until I pass too."

Durham died last Friday and was one of Gaga's biggest supporters as a former manager of her Haus of Gaga creative team. She was also the person who inspired the song "Grigio Girls" on Gaga's Joanne album. Just last month at Coachella, the Grammy Award-winning artist dedicated a rendition of her hit song "Edge of Glory" to her now late BFF.

Some of their most memorable moments this year were during Durham's wedding planning process, in which Gaga was literally her right hand. She wrote about all the ways her best friend was by her side as she continued to fight her stage IV cancer on her blog last month.

"Honestly, if it wasn't for Gaga and the financial contributions from everyone so far I really do not think I would be here," Durham expressed. "Let's just say I understand why people give up and die because they do not have the resources that I have been given. It's really given me some thought on starting a non-profit."

"I vow to be a little stronger every day for her because that's what she would have wanted, I vow to be stronger for anyone who's lost somebody to cancer," Gaga continued in her moving post. "I'm a part of that family now. I vow to be a warrior for her and be a voice for cancer patients, so the world can continue to improve the dialogue and fight. I loved her. I still love her."

We send our most sincere condolences to Durham's family and Gaga.