Eminem says the track 'Castle' on his new album is a message to his children about his regret for missing Christmas when he overdosed.

The 'Walk On Water' rapper, whose 21-year-old daughter Hailie's birthday is on Christmas Day, was hospitalised in December 2007 after suffering a severe methadone overdose which doctors say almost killed him, and he has admitted it was a ''rough'' time.

Eminem revealed on his SiriusXM Shade45 channel: ''The 'Castle' song basically takes place in 2007, which leads to the overdose, which leads to Christmas and her birthday and me missing that because I was in the hospital. Me not being there for my kids for Christmas was rough.''

The 45-year-old hip hop star - who also has custody of Hailie's cousins Alaina and Whitney and his younger half-brother Nathan - admitted the track on new album 'Revival' is a recreation of his overdose experience.

He told Billboard: ''And if you listen to 'Castle' all the way through, you hear me taking pills and falling; that was the re-creation of me falling in the bathroom and then waking up in the hospital and not knowing what the f**k was going on. I had tubes in me, I was angry and I couldn't talk at all.''

The 'Love The Way You Lie' hitmaker also revealed he is still considering the possibility of a 'Revival' tour.

Eminem said: ''I don't know - possibly. Who knows? It's something that's being thought about. It's not a 'no' right now, let's just say that. It is possible.''

The rapper launched his new album earler this month with a pop-up spaghetti shop, Mom's Spaghetti, in his hometown of Detroit, paying tribute to a popular internet meme based on his track 'Lose Yourself'.

Referencing a lyric from the powerful call to arms, featured in his 2002 movie '8 Mile', he tweeted: ''Detroit! Come vomit up some spaghetti with me this weekend at our official #Revival pop up. Exclusive merch, spaghetti and more. (sic)''

The album features a number of collaborations, including Beyoncé, Ed Sheeran, Pink and Alicia Keys.