Credit: Taylor Hill/

Though they showed up to fete their former boss' birthday, things aren't looking so rosy these days for employees of Rosie O'Donnell's canceled OWN program.

O'Donnell feted the big 5-0 with an 80s-themed bash at Chicago hotspot Paris Club Monday night.

The talk show host showed up with fiancee Michelle Rounds, and used the evening to honor 50 real women celebrating five decades of life, too. Also on the guest list? Mike Tyson, who brought out O'Donnell's three-foot cake, and members of The Rosie Show's production team.

"Rosie kicked off the festivities by thanking those in attendance," a partygoer tells Us Weekly. "She addressed her show's cancellation with a positive outlook. She encouraged [The Rosie Show] team to have a great time despite the setback."

Though O'Donnell was in good spirits during her party, insiders tell Us that her split from Oprah Winfrey's network wasn't exactly amicable.

"The entire show was a disaster, and Oprah was definitely over Rosie being so erratic," the source admits. And, despite being aware of The Rosie Show's low ratings, O'Donnell's team may not be quite as at peace with the program's abrupt end as they seemed Monday evening. "Rosie didn't even have the decency to tell them [about the cancellation] herself," the insider shares. "She wasn't present for the announcement on Friday."

The Rosie Show's final episode will air March 30 at 7/6c on OWN.