Nick Cave has opened up about the death of his teenage son in a harrowing letter.

“It seems to me, that if we love, we grieve. That’s the deal. That’s the pact.”

These are the poignant words of iconic Australian musician Nick Cave in reference to the tragic death of his son, Arthur, who fell from a cliff in 2015.

The poetic words appeared in a harrowing letter about grief the Bad Seeds frontman penned to a fan dealing with the death of her father, sister and first love.

Responding to a question on his website, The Red Hand Files, where Cave was asked by a fan whether he felt that his son, Arthur, was still communicating with him.

“[I] feel that I have some communication with them, mostly through dreams”, the fan wrote with regards to her experience with death before posing the emotional question.

Cave thanked the fan for her “beautiful question”, before sharing the feelings of grief he’s felt in the years since his son Arthur Cave suffered a fatal brain injury after plunging onto the underpass of Ovingdean Gap in Brighton, England, aged just 15.

“I feel the presence of my son, all around, but he may not be there. I hear him talk to me, parent me, guide me, though he may not be there,” he wrote.

“He visits Susie in her sleep regularly, speaks to her, comforts her, but he may not be there. Dread grief trails bright phantoms in its wake.”

Nick Cave's emotional open letter to a fan.

He went on to say that "grief was the price of love" and that the two emotions were "forever intertwined".

"Grief is the terrible reminder of the depths of our love and, like love, grief is non-negotiable. There is a vastness to grief that overwhelms our minuscule selves."

He said the "communication" we feel from loved ones lost in dreams, through voices or visions, are "willed in to existence" to aid the healing process.

"These are precious gifts that are as valid and as real as we need them to be. They are the spirit guides that lead us out of the darkness."

Cave, 61, is also mourning the loss of his Bad Seeds bandmate, Conway Savage, who died earlier this year.

Savage passed away in September at age 58 after undergoing treatment for a brain tumour last year.