Mac Miller raps about his ''personal demons'' on a new track with Seth Hirsch.

The late rap star - who died of a drug overdose in September - posthumously appears on the track 'Say Goodbye', which Seth says offers a ''window into Mac Miller's soul''.

Mac raps: ''Living with a heart that's broken/ We know how that feel/ We always caught up in the moment/ And this ain't no drill, one shot one kill/ Just pop one pill, you'll be good by the morning.''

Seth's perception of the track - and of Mac's verse, in particular - has changed since the rapper's death.

He shared: ''The song's about toxic relationships, and dealing with someone who's s***ty towards [you], sucks up all your energy, and keeps taking advantage of your time and emotions.

''After Mac passed away, I realised this song was about a lot more than that.''

Seth thinks the record will give fans an insight into Mac's pain prior to his death.

He told Complex: ''It's really about struggling to say goodbye to our personal demons and the chains they put on us. ... This song is such a window into Mac Miller's soul and what he was going through.''

The release of 'Say Goodbye' comes shortly after Ariana Grande expressed her anger that Mac didn't win a Grammy Award at the recent awards bash.

Ariana - who began dating the late star in August 2016, before they split in early 2018 - tweeted ''f**k'' and ''trash'' when Cardi B won Best Rap Album for 'Invasion of Privacy'.

However, Ariana subsequently insisted she hadn't meant to shade the 'Bodak Yellow' hitmaker.

She wrote: ''[The tweets had] nothing to do w [Cardi]. good for her. i promise. i'm sorry.

''She's not [trash] at all and that's not what i meant and u know that. (sic)''