Arsenal manager Arsene Wenger told Jack Wilshere he must "master his life" after confirming the Gunners midfielder had apologised for being photographed holding a shisha pipe at a nightclub.
Wilshere, 23, who is nearing a return to first-team action following ankle surgery, generated unwelcome headlines after pictures were posted on social media following a night out in London.
It was not the first time Wilshere has found himself in an unflattering photograph after he was pictured smoking in Las Vegas last year with England goalkeeper Joe Hart after the World Cup.
Wenger, speaking Friday ahead of Arsenal's north London derby against Tottenham Hotspur this weekend, said Wilshere had apologised and that the player had been reminded of his responsibilities.
"I have spoken with him about that (smoking) and he is not a smoker," Wenger said. He is of course sorry for what has happened.
"It is down to him to master his life. He had the day off the next day and he went out to watch the Super Bowl.
"When he is here he has to follow the rules that we dictate here. When he is out of his job, it is his own responsibility to behave like he wants to behave."
The veteran French manager added: "I believe his photo has been taken at half past 12 when he watched the Super Bowl. I don't know any more of what happened and it's not of a big interest."
Thursday saw Wilshere post a video of himself in training as he recovered from ankle surgery along with the message: "Worry about your character not your reputation, because your character is who you are and your reputation is only what people who don't know you think about you!"
Wenger added Friday that much of the recent publicity surrounding Wilshere was unfair to a player whose career has been blighted by injury.
"You are always worried for your players that they get what they don't deserve, but I think I observe him well and he behaves in a very professional way," Wenger said.
"Jack has gone through some bad spells in his career and always recovered.
"It would be wrong to give him that kind of (bad) reputation because he is a serious player and he works very hard.
"He is two weeks ahead of schedule in his (recovery) training, and you don't do that if you are not serious."
Wenger also told reporters: "You have been 20 as well. You need sometimes to relieve the pressure a bit.
"Today it is much more difficult because everywhere you go people make photos and a photo shows one second of your life.
"It doesn't define who you are," added Wenger, who took action against Wojciech Szczesny after it emerged the Arsenal goalkeeper had smoked a cigarette in the showers following the 2-0 defeat at Southampton on New Year's Day.
Arsenal have won their last five games and Wenger warned that a fully-fit Wilshere would not be guaranteed a first-team place.
"Any player has a battle in our squad now," he said.