Mac Miller spent the night before he died watching football with friends.

The American rap star was found unconscious at his home in the San Fernando Valley at around midday on Friday (07.09.18), and pronounced dead at the scene by paramedics after he went into cardiac arrest following a suspected overdose.

However, friends are shocked by his death as the rapper - whose real name is Malcolm McCormick - had enjoyed a quiet evening with pals the day before.

A source told PEOPLE: ''He was just out with friends watching the game last night, that's why this is such a shock.

''Everyone who he worked with was aware that he was delicate, but thought it was because of the new album, nerves, nothing like this.''

Mac - who had battled substance abuse issues for years - released his latest album 'Swimming' on August 3.

Speaking previously, Mac admitted he had battled drug addiction and depression.

He said in 2013: ''I love lean; it's great... I was not happy and I was on lean very heavy. I was so f***ed up all the time it was bad. My friends couldn't even look at me the same. I was lost.''

He added in 2015: ''I had a drug problem for a long time. It wasn't just in music, but I definitely was going through a drug problem and I think it was more my state of mind. I was just pretty depressed.''

However, he said he got sober because ''overdosing is just not cool''.

He said: ''I hate being sober [but would] rather be the corny white rapper than the drugged out mess who can't even get out of his house. Overdosing is just not cool.''

Prior to his death, Miller had been sharing behind-the-scenes videos of his home life on his Instagram account.

In the video clips, the rapper - whose two-year relationship with Ariana ended in May - showed a turntable that played his track 'So It Goes'.

Earlier this week, Miller spoke candidly about his trouble dealing with the pressures of fame.

Reflecting on the stresses of success, he said: ''There's pressure. A lot of times in my life I've put this pressure to hold myself to the standard of whatever I thought I was supposed to be, or how I was supposed to be perceived.

''It's the job. This is what I signed up for. So, you just have to not. You have to have your own reality and that has to be the driving force of your life.

''Do I wish that every single thing I did when I was 19 wasn't a discussion? Sure.''