US rappers OutKast have been told off for a poster they used that showed singer Andre 3000 holding a gun.
The people in charge of advertising in the UK got complaints about the poster because the gun was smoking, so looked like it had just been fired.
OutKast's record company said the poster was like ones often used for films and thought people would have known it wasn't promoting violence.
But advertising bosses said it made guns look cool and was "irresponsible".