Backstreet Boys have announced plans for a tell-all documentary to celebrate their 20th anniversary.The five piece - comprised of Brian Littrell, Nick Carter, A.J. McLean, Howie Dorough and Kevin Richardson, who rejoined last year after taking some time out - have hired Katy Perry's 'Part of Me 3D' co-producer Stephen Kijak to direct the tell-all movie.The group said: "We always wanted to make a film and now is the ideal time. With Kevin back, the fact that we are masters of our own destiny, a new album in the works and our 20th anniversary -- it all adds up to being the right time to share our story."Stephen has promised it will be a no holds barred look at the group and revealed their openness was one of the main reasons he wanted to work with them.He told the Hollywood Reporter: "What drew me to this project is their openness and willingness to push themselves into uncomfortable places, to be vulnerable and honest."The group are also working on plans for a 20th anniversary tour and album.