Al Pacino is officially a father at 83 ... his girlfriend, Noor Alfallah, gave birth and the two are already out and hitting the town together as a couple.

Sources close to the couple tell us Noor recently gave birth, and both parents are ecstatic. We don't yet know the sex of the baby.

And get this, Al and Noor were spotted out for dinner together in L.A. Wednesday, hitting up Sunset Tower. On the way out, Al rode shotgun with Noor behind the wheel ... you can also see what appears to be a car seat in the back, unclear if Baby Pacino tagged along.

The two definitely appear to be in great spirits, and obviously have a lot to celebrate. TMZ broke the story the 2 were expecting last month, at the time, we were told Noor was about 8 months along.

Al and Noor have been an item since April 2022, but as we first reported, the pregnancy came as a total shock to Al -- with sources saying he wasn't planning on a 4th kid.

What's more, we were told Al was convinced he couldn't have any more kids this late in the game due to medical issues that should've prevented the whole thing, but alas, he's a Daddio once again.

We reached out to Al's rep for comment ... so far, no word back.

Congrats to the whole fam!!!