A woman claiming to be Avicii's 'secret girlfriend' has penned a heartbreaking letter. 

One week since the death of 28-year-old Swedish DJ Tim Bergling made headlines around the world, a Czech woman named Tereza Kačerová has posted a heartbreaking letter to Instagram, speaking about her intimate relationship with the man better known as Avicii.

“I’ve spent the last few days waiting to wake up, waiting for someone to tell me that this is some sick joke,” the 25-year-old model began.

❤️ Part 1/2

A post shared by Tereza Kačerová (@terezakacerova) on Apr 26, 2018 at 7:35pm PDT

“When I saw they had changed your bio on Wikipedia from ‘is’ to ‘was’, I sobbed… You are too young and wonderful and I love you too much…”

The mother-of-one explains in the letter that she desperately wanted to keep their relationship private because she wanted “no part in that madness”. She also discloses the plans they had to have a child.

“Every time I think about something we won’t finish, I feel physical pain in my heart,” she continues in the letter which has been liked more than 30,000 times.

❤️ Part 2/2 *** NOTE: Mexican Coke = Coca Cola obviously. ***

A post shared by Tereza Kačerová (@terezakacerova) on Apr 26, 2018 at 7:37pm PDT

Kačerová writes extensively about Bergling’s relationship with her son, and the travelling they did together. She laments the fact she will never visit Sweden with him in the summer time, or take him to South America.

The day prior to posting the letter, Kačerová shared a compilation of photos of her with Bergling and her son. They appear at dress up parties, eating popcorn in bed, playing the piano and skiing together.

The brightest stars burn out the fastest.

A post shared by Tereza Kačerová (@terezakacerova) on Apr 26, 2018 at 7:31pm PDT

Kačerová captioned the images: “The brightest stars burn out the fastest.”