Grealish jokingly likened teammate Riyad Mahrez's ineffective performance against Aston Villa on the final day of last season to Almiron's for Newcastle.
The incident was recorded during Manchester City's title celebrations and made its way onto social media but Almiron has since had an upturn in form, scoring eight goals in 15 Premier League games to help Newcastle up to third on the table.
Almiron was also named Premier League player of the month for October.
"I haven't actually been asked about that and let me just address it," the England international told The Independent.
"It was the day after the season finished, and obviously I'd had a few drinks.
"Straight after that, because I didn't realise, we were out celebrating, and I wasn't on my phone on social media. I remember I was in Ibiza, and it had obviously come out. That was one thing I regret.
"I'm actually buzzing the way he's reacted. He said something about me in the interview the other day, he wished me the best. I thought 'what a guy'.
"Because if that was me, and somebody had said that about me, I'd have probably been the other way and been like 'f**k it'.
"I messaged [Newcastle defender] Matt Targett because I'm close with him from Villa and I said to him 'can you message him for me and say to him that I apologise? I obviously didn't mean it'.
"When I look back on that, that was just one thing that was stupid of me to say. I shouldn't have said it. I didn't realise it was a video to go out, I thought it was just private. But even in private, I shouldn't have said it because he's a fellow professional.
"I'm actually buzzing for him, I've had a lot of stick off the Newcastle fans and rightly so. At the end of the day, they are backing their player, which I fully understand. He seems like the most harmless, nice guy, so fair play."
