Will Smith is writing a book.

The 49-year-old actor has revealed he's teaming up with self-help author Mark Manson - who wrote 'The Subtle Art of Not Giving a F**k' - to pen a memoir-come-inspiration paperback filled with ''stuff'' he's gathered over time for the world to read.

Taking to his Instagram account, he said in a video: ''I'm writing a book! I got years and years of stuff I want to say, and I'm finally going to write a book for y'all.''

He then asked Mark: ''Are you feeling confident? Are you feeling like we'll be able to do transcendent art with this book?''

Mark replied: ''I spent the last six months with crippling anxiety, but today I feel great.''

The former 'Fresh Prince of Bel-Air' star then joked that him and Mark have a meeting with five publishers coming up and they're ''sure'' they'll go with the ''highest bidder.''

He quipped: ''We're going to be meeting with five publishers...

''We're gonna pick one. And if I had to take a guess, I feel very confident that we're gonna go with the highest bidder... I'm just saying.''

According to the New York Post newspaper, the book is yet to be written.

A source said: ''It's supposedly going to be a memoir slash inspirational book.''

Will has been very open about how his mind works over the years and recently admitted that although he's had ''all the sex he's ever wanted'' it doesn't make him happy because he believes being ''useful to others'' is the only thing that'll bring peace.

He said: ''The idea is ... I've been to the top of money, I've had all the sex that I've ever wanted, I've had all of the adoration.

''I've been to the top of all those material world mountains and nothing makes you happy other than being useful to others. That's it. That's the only thing that ever will satisfy that thing, is that what you're doing is useful.''