Joe's exes were filmed strolling inside NYC's Hotel Barriére Fouquet Thursday night to hang out with friends -- amid Sophie's ugly divorce to Joe.

Sophie, dressed casually in a white t-shirt and gray skirt, arrived first for a girls' night out take two with Taylor -- who once dated Joe for a few months in 2008.

Moments later, Taylor rolled up in an SUV driven by a chauffeur with two beefy bodyguards to protect her. Looking classy and chic, Taylor stepped out of her ride and sauntered inside the hotel with several pals following behind.

On Tuesday, Taylor and Sophie were photographed walking arm and arm into Via Carota restaurant for a sit-down dinner, Italian style. Coupled with last night's outing, the two are fast becoming BFFs.

All this comes as Sophie and Joe duke it out in divorce court -- and now federal court. As we reported ... Sophie filed a lawsuit against Joe hours before her second meet-up with Taylor.

In the suit, Sophie accused Joe of unlawfully keeping their children in the Big Apple instead of allowing them to return to England with her. She even cited a child abduction law.

Joe categorically denied the accusations, saying it's Sophie who has crossed the line by violating a Florida court order that restricts both parents from relocating their kids.

Here's the reality ... even if Joe and Sophie made a deal when they were together that they'd move to England, that deal is not binding on the divorce judge. The judge's North Star is what's in the best interests of the 2 kids -- deal or no deal.

Weeks ago, Joe filed for divorce from Sophie in Dade County, claiming their 4-year marriage was irretrievably broken and asking for joint custody of their 2 young daughters.

Do you think Sophie Turner is intentionally going out with Taylor Swift to get back at Joe Jonas? Vote below.