Singer Aloe Blacc was heartbroken when he read the lyrics to late pal Avicii's song S.O.S. because the whole track is a cry for help.

The star had a massive hit with his Avicii collaboration Wake Me Up, and the DJ's record label bosses asked him to sing on S.O.S. for the tragic electronic dance music icon's posthumous album, TIM.

A quick read through of the lyrics made Aloe Blacc realise that if anyone had paid attention to what his friend had written, they might have been able to get him the help he needed before he took his own life in April, 2018.

"I got the lyrics from the record label and I looked at them and I thought, 'How am I getting this S.O.S. as a song after Tim's gone,'" he tells Good Morning America. "It felt like... all of us really wanted to have this message way before, so that we could have been there to support him.

"He had written in his notes that he wanted me to sing this song, but he never communicated that to me. He communicated other things via emails and text messages..."

Aloe Blacc was flattered that his DJ pal had requested him for the track, which was among the new music Avicii sent to his producers before his death.

"I was super impressed with the way that he could create melodies on the drop of a dime and come up with great productions and sonic landscapes and he was impressed with my voice...," he adds. "I think he just knew with this song I could attack it and accomplish what he was looking for. I'm glad that I got a chance to do that."