U2 fans are calling for those attending the band's Belfast shows in the SSE Arena to wear white and wave something white to make a statement in the name of peace.
The Dublin band's show will be its first since their cancelled Paris concerts in the wake of the atrocities in the French capital.
Bono said while the band did not take the decision to cancel the concert, he understood the decision and that it was "totally the right thing to do".
The band said they watch the events unfold in "disbelief and shock" and they were devastated.
"Our hearts go out to all the victims and their families across the city tonight."
Copenhagen woman Connie Maria Westgaard has called for fans to wear white to the Belfast shows.
She has also called for fans to wave something white when the band arrive on stage and during the performances of Sunday Bloody Sunday, Raised by Wolves and One - if they play them.
On Facebook, Connie wrote: "Belfast has its own history of terror and violence, so it seems like the right time and place to make a statement in the name of peace, love and music and pay our respect to the victims of terror and violence all around the world."
The post has been shared across social media and many fans have joined in the call for all to join in.
U2 have stirred up controversy ahead of their show in Belfast, their first in the city for almost 20 years.
The supergroup have included a musical and pictorial tribute to the victims of the 1974 loyalist bombings of Dublin and Monaghan as part of their stage set for the tour during the Raised by Wolves song.
Last week guitarist The Edge was adamant the band would not leave out the song.