Lady GaGa will be airing her Netflix documentary 'Five Foot Two' instead of having support acts on her 'Joanne UK Tour.

The 'Million Reasons' hitmaker revealed her unusual opening surprise on Twitter letting the Barcelona fans know about the screening, which would have lasted almost two hours.

Gaga - who was reported to be engaged to talent agent Christian Carino - wrote on the micro-blogging site: ''I've decided to play the documentary made about me every night before the show. If you get there early it will be on. Tonight starts at 7pm Barcelona time! #JoanneWorldTour #JoanneWorldTourBarcelona (sic)''

The movie - directed by Chris Moukarbel - was released in September, and explores the ''lonely'' and ''isolating'' parts of fame.

In a post to her follows, Gaga said previously: ''With 'Gaga: Five Foot Two', I found myself witnessing myself in a way I am unable to see on my own. I felt proud, I felt sadness, I felt empowered, I felt vulnerable ... but what struck me the most was the film's authenticity in the way Chris [Moukarbel], the director, chose to show my lowest lows, my highest highs, and the close relationship with my family that I clung to fiercely while writing my album 'Joanne'.

''Although surreal, happy and also hard, I'm most touched that the veil behind the aura of my fame reveals that fame is not all it's cracked up to be. It is lonely, it is isolating, and it is very psychologically challenging because fame changes the way you're viewed by people. For me, it feels very unnatural, but complicated because I know it is my destiny to be a performer.''

The UK leg of the 'Born This Way' star's global run kicks off at Birmingham Arena on January 31.

Lady Gaga's 'Joanne UK Tour' dates are as follows:

January 31, Birmingham Arena

February 1, Birmingham Arena

February 4, London, O2 Arena

February 6, Manchester Arena

February 8, London, O2 Arena