The mystery man turns out to be Kevin Yorn, who is not just a high-powered lawyer ... he's Scarlett's lawyer.
ScarJo and the guy we'll just call Lucky, for now, had a romantic dinner at Scalinatella on the Upper East Side over the weekend. Afterward, they strolled the streets and held hands like a couple o' newly dating kids tend to do.
Earlier this year, Scarlett filed for divorce from Romain Dauriac -- but she's clearly not putting herself on the shelf.
Most recently, she reportedly went on a few dates with 'SNL'er Colin Jost.
When he sees the dress Scarlett wore for date night, 3 words gotta come to mind for Colin ... snooze, ya lose.