"Stranger Things" filming is kicking into high gear ... notable cast members are getting together to shoot some of their final scenes -- and it's looking hella emotional.

We got pics of the gang on set, shot Thursday in Atlanta, and while you can make out the figures of and coming to set -- it's the kids who take center stage ... though they definitely aren't kids anymore.

Check it out -- and , who play love interests on the show, are filming a scene at the top of the hill .

.. it seems quiet and emotional, not like the rip-roaring action the show also features.

But, speaking of emotional -- is that an intense scream we can see MBB ready to make ... something her character Eleven's done quite a few times during the show's first 4 seasons?

BTW this scene takes place on a radio station set ... we don't think Eleven and Mike are recording a fire mixtape in season 5 -- but hey, music did save the day last season.

Big takeaway ... the kids are all grown up.

Millie's 19 and to

's son and FH is 21 -- old enough to crack open a cold one at the end of a long shoot.

This is becoming a trend for the "Stranger Things" cast ... remember, we last week in Georgia, and he didn't look anything like the 13-year-old he was when the first episode dropped back in 2016.

No release date on the new season of 'ST' yet ... but with so much film rolling this month ya gotta think the last lap's coming real soon.