Footage of Arsenal players inhaling nitrous oxide, more commonly known as "balloons" or "happy crack", emerged last night.
A number of Gunners stars were in attendance at the 'champagne and vodka party' in a VIP area of a West End Nightclub in August prior to the Premier League season getting underway.
And in videos/photos posted by The Sun, Alexandre Lacazette, Mesut Ozil, Pierre-Emerick Aubameyang, Sead Kolasinac and Matteo Guendouzi are all seen inhaling the laughing gas, which is not illegal but has its health risks.
As per The Telegraph, it is known to cause feelings of euphoria, hallucinations and fits of giggles and laughter - and one can even pass out if too much is taken - which is what appears to happen to Guendouzi in the clip.
Henrikh Mkhitaryan and Shkodran Mustafi also feature in the video but are not seen with the substance.
An Arsenal spokesman said that the players will be "reminded of their responsibilities as representatives of the club".
The use of nitrous oxide in balloons has becoming increasing popular at parties. Footballers Raheem Sterling, Kyle Walker and Jack Grealish have all been embroiled in scandals for taking it in the past.
Arsenal started the campaign with consecutive defeats to Manchester City and Chelsea but have embarked on a brilliant 20-game unbeaten run under new boss Unai Emery.
The North London club sit in fifth in the Premier League table, only behind fourth-placed Chelsea on goal difference.