U2 posted a picture of their lively Dublin crowd on Saturday night (22.07.17) - but the photo stood out due to one fan.

The Irish rockers - made up of Bono, The Edge, Adam Clayton, and Larry Mullen Jr. - took to their Twitter to upload the image of their 80,000 capacity crowd at Croke Park, but didn't spot one guy in the front row flicking them an inoffensive two-fingered gesture.

U2 captioned their picture: ''Full house tonight. #U2 #croker #dublin #U2TheJoshuaTree2017 (sic)''

The majority of the audience appear to have thoroughly enjoyed the band's performance as they can all be seen cheering and throwing their arms aloft with joy.

U2 brought their hit album 'The Joshua Tree' back to Dublin 30 years after they toured the record.

Several stars were in attendance to see the monumental occasion, including 'Fantastic Beasts and Where To Find Them' actor Colin Farrell, The Pogues frontman Shane McGowan, and President of Ireland Michael D Higgins.

The group performed the album in full as well as a number of other hits, such as their 2004 hit 'Vertigo'.

They concluded their set with 'Ultra Violet (Light My Way)', 'One' and 'The Little Things That Give You Away'.

U2 also played the first track on 'The Joshua Tree' album, 'Where the Streets Have No Name', at the concert - but Bono recently admitted the tune is ''unfinished''.

He said: ''Musically it's great and the band deserve credit for that, but lyrically it's just a sketch and I was going to go back and write it out.

''Half of it is an invocation, where you say to a crowd of people 'Do you want to go to that place? That place of imagination, that place of soul? Do you want to go there, because right now we can go there?'

''To this day when I say those words you get hairs on the back of your neck stand up because you're going to that place.''