The star, real name Devonte 'Dev' Hynes, reveals he is still reeling from the news of the model and Tv personality's death, which hit headlines on Monday (07Apr14) after she was found dead at her home in Kent, England.
He has opened up about their long friendship in a blog post online, but admits he "really struggled" to convey his real feelings as he continues to try and come to terms with her loss.
He writes, "Nothing I could write, say, or any pictures I feel can really, truly convey the loss we are feeling right now...
"This is someone who affected so many of us, my friends, in our lives. It's a struggle to picture a moment in time without her. Just last month while playing shows in London I remember the delight of seeing her and (her sister) Fifi together, just like old times. We quipped about it, a little older, but still babies in the grand scheme of things.
"But really, she had grown so much, we all watched her grow, and create a beautiful family with Thomas (Cohen, husband). My heart (goes) out to him, and the rest of her family. This is just so unfair... it's made me physically sick."
At a loss for words, Hynes concludes the post by adding, "I don't have much more to say, i'm still in shock over this. I just wanted to try and honour her in some way... We love you Peaches. Rest In Peace."
Initial autopsy results have proved inconclusive and Geldof's cause of death is not expected to be determined for several weeks.