City have finally won the Champions League, doing so at the Ataturk Olympic Stadium in Istanbul on Saturday night with a 1-0 win over Inter Milan.
Rodri scored the winning goal that also saw Pep Guardiola win the treble for his side, the second of his career after doing so with Barcelona in 2009.
The celebrations have been wild, going on through the night and the players did not look like they were slowing down any time soon.
A post timestamped at 7:33 AM saw the City stars still out in full force.
Grealish stood with Kyle Walker, Erling Haaland, Kalvin Phillip and John Stones, singing a song dedicated to the England defender.
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But while the rest were in their normal clothes, Grealish was still in his City kit from the match.
Nevertheless, the England international looked in fine spirits as he gave the crowd a rendition of 'Jonny, Jonny Stones'.
The former Aston Villa star was emotional after winning the Champions League with City in his second year at the club.
He gave an incredible interview to BT Sport where he could not put into words the achievement he had managed.
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And the songs did not stop there when Grealish managed to steal the microphone and start up his own chant.
Goading the crowd to sing along, the winger began: "Have you ever won the treble, have you f***."
Gradually, those present joined in before it became a rousing chorus with players, fans and staff members getting involved alike.
Looking a little leggy with a hoarse voice, that did not stop the 27-year-old, who looks like he had been up all night.
Grealish is often lauded for wearing his heart on his sleeve when speaking to the media and he was full of emotion when speaking to Jake Humphrey and Rio Ferdinand.
"This is just what you work your whole life for," he said. "I'm so happy, man.
"I played so dead today I was awful, I don't care though. Honestly, to win the treble with this group of players and this staff it's so special.
"Anyone that knows me knows how much of a family person I am and how much I love football and I don't know, this is what I've worked for my whole life.
"You think back to all the people that have helped you along the way and just seeing my family in the crowd there, it just makes me emotional."
Just a quick look at Grealish's social media channels shows that he and the City side had quite the night to remember.
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The pictures showed Haaland smoking a cigar and wild celebrations in the dressing room.
And kit man Brandon Ashton, renowned for being a popular member of the team, even stripped down to his underwear before dolphin diving in a stream of booze.