"Today is exactly 30 YEARS since The @FreshPrince of Bel-Air debuted!" the 51-year-old actor wrote.
"So we're doin' something for y'all... a for real Banks Family Reunion is comin' soon to @HBOmax!"
Paying tribute to the late James Avery, who played Uncle Phil, he added: "RIP James. #FreshPrince30th."
The photos were also shared on the official Fresh Prince Instagram page, with the caption: "Still family after all these years!"
In one of the photos, which have also been released by HBO Max, Smith can be seen in the foreground alongside his on-screen family, with Alfonso Ribeiro, Jazzy Jeff, Daphne Reid, Karyn Parsons, Tatyana M. Ali and Joseph Marcell all smiling at the camera.
In the second image, Smith is sitting down with original Aunt Viv Janet Hubert - who famously fell out with Smith due to on-set issues, and quit the show after just three seasons.
Having sat down in front of the camera together for the first time in 27 years, it looks like the hatchet may finally be buried.
Many fans commented to say how 'iconic' and 'legendary' the photos were was, with some saying it felt like a massive blast from the past.
One said: "This is epic! 30 years? That's incredible. This will be special."
Another added: "Iconic. Miss this show, can't ever forget the opening song."
The reunion is being organised by HBO Max and produced by Smith and wife Jada Pinkett Smith's media company Westbrook Media, especially to coincide with the show's 30th anniversary.
Formatted in a similar way to the Friends unscripted reunion, the Fresh Prince gang won't be returning for a new episode, but instead are coming together to look 'back at the series and the cultural impact [it] has had since its debut'.
It follows a similar virtual meet-up in April, when the show's cast reunited for Smith's lockdown Snapchat series Will From Home.
Things got very emotional when the cast paid tribute to Avery, who died in 2013 from complications associated with open heart surgery.
During the video call, Will said to his castmates: "That just makes me teary. The first couple times that I'm seeing clips of James, you know?"
He added that the reason why he got so emotional was because he is still connected with the cast that he spent nearly six years with.
"You guys are my second family. I've been shaped by my interactions and relationships," he said.
"When I look back, the best times in my life will have been on that set."
The HBO Max reunion special is due to air in November, but in the meantime viewers can watch every episode of The Fresh Prince of Bel Air on HBO Max.