Emma Stone, Tom Hanks, More Celebs Attend Paul McCartney's 2nd Surprise Concert

Paul McCartney's pop-up gig Wednesday night was star-studded with a little help from his friends ... 'cause the show brought out a strawberry field's worth of stars!

The singer-songwriter played New York City's iconic Bowery Ballroom after selling the place out Tuesday ... and, ya gotta check out all the arrivals eager to watch the Beatles singer perform.

Robert De Niro and his baby mama Tiffany Chen led the charge -- though it looks like it was past their 1-year-old daughter Gia's bedtime. While Robert and Tiffany made it a date night, Emma Stone chose to focus on family rather than her man ... bringing her mom instead.

Tom Hanks and Rita Wilson -- two huge music lovers -- made the trek out ... and comedian pals Jerry Seinfeld and Amy Schumer got the chance to see each other too.

Among the others in attendance ... Robert Kraft and his wife Dana Blumberg, Cara Delevingne, Anne Hathaway and her husband Adam Shulman, Andy Cohen, and Steven Van Zandt, just to name a few.

Paul announced the second performance online at about 10 AM Wednesday ... and, tickets reportedly sold out within the hour. Doors to the venue opened at 5 PM and the show kicked off at 6:30 PM.

Like we said, McCartney pulled a similar move Tuesday ... so, keep your eyes peeled on his social media, in case he wants to pull off the three-peat.