Swedish DJ Avicii had a secret girlfriend and was a doting step-father to her young son at the time of his death.
Model Tereza Kačerová posted a heartbreaking open letter on her Instagram, in which she revealed that the pair had been planning on having children of their own.
She also posted a video of photographs from their time together, showing Avicii's close relationship with her son Lucas, reports Daily Mail.
Avicii, whose real name was Tim Bergling, was found dead in the city of Muscat, Oman, on Friday last week.
"Dear Tim," Ms Kačerová writes in the letter to the late 28-year-old. "I've spent the last days waiting to wake up, waiting for someone to tell me this is some sick joke, some awful mistake. I think it's finally settling on me now that I will truly never get to see you again".
In her letter, she reminisces of their time together and speaks of their plans for their future.
"I used to tell you that Luka will never remember a life without you. Now I hope that he will remember his life WITH you. I'll be there to remind him. I'll show him
"Every time I think about something we won't finish I feel physical pain in my heart.
"We never finished the Harry Potter marathon - we had the last one left - you never witnessed me having a meltdown when Snape dies.
"I never finished persuading you that our daughter's name MUST be Serafina.
"You never finished your tattoo sleeve in which the inner forearm would have a face coincidentally resembling mine."
She continues: "I was always very set on keeping our relationship private because I wanted it to be OURS and ours only and wanted no part in that madness.
"But I thought, if I'm going to share this with the world, it will be when I'm pregnant with our child. Ohhh how that plan went awry."
I called you baby angel. Little did I know how soon you would become one.
"The last words you ever said to me were 'I love you'. Well I LOVE YOU. As much as you love Mexican Coke... and then some."
Despite a meteoric rise to success following the release of hit-single Le7els in 2011, Avicii announced in 2016 that he would not longer perform live, following years health problems caused by stress and alcohol abuse, as well as severe anxiety.
A recent documentary, Avicii: True Stories shed light on the extreme pressure he was under, performing 320 shows in a single year.
In the documentary, Avicii, a self-confessed introvert, speaks frequently about using alcohol as a crutch to be able to perform, drinking every day during his hectic tour, and to help him with his crippling anxiety and stress.
At the age of 21 he was diagnosed with acute pancreatitis - a potentially life-threatening inflammation of the pancreas - due in part to excessive drinking.
In 2014, Bergling was again hospitalised and forced to have his gallbladder and appendix removed.
Avicii made a fortune during his short career, cashing in $28million in 2014 alone, earning $250,000 a night when playing out sold-out shows, according to GQ.
Avicii himself was less bothered about his millions, saying in 2013 that he 'noticed straight away when I started making money, that I don't need that much money'.
In 2012 he donated the entire income of his U.S. tour - more than one million dollars - to hunger relief charity Feeding America, and in 2013 he gave one million euros to Swedish aid organisation Radiohjälpen.
Bergling grew up in affluent Ostermalm in the Swedish capital Stockholm, and began producing music in high school.
He made a name for himself on the EDM (Electronic Dance Music) scene, before his breakthrough hit Le7els in 2011.
Swedish DJ-producer, Avicii, whose name is Tim Bergling, was found dead, Friday April 20, 2018. Photo / Supplied
He would later become known for hits like Wake Me Up!, You Make Me, and recently Lonely Together, a collaboration with Rita Ora.
He won two MTV Music Awards, one Billboard Music Award and earned two Grammy nominations.
Just three days before his death, in his final post on Twitter, Bergling thanked the Billboard Music Award's jury for his nomination int the Top Dance/Electronic Album category for his EP Avīci (01).
He died on April 20 in Muscat, Oman, where he is reported to have been holidaying with friends.
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