Mayor de Blasio abruptly ended his daily exercise session at the Park Slope Y when confronted by a homeless activist — admonishing her, “I’m in the middle of doing my workout,” according to a video posted online Friday.

The video shows Hizzoner executing an intense butterfly stretch when the woman approached on Thursday to push for more housing for the homeless.

“I’m in the middle of doing my workout, I can’t do this now,” the mayor responded.

With his security detail blocking the woman, de Blasio quickly got up and scurried away.

“He made it clear that his morning workout was more important to him,” Nathylin Flowers Adesegun told Patch NYC. “Am I just supposed to stay homeless?”

Adesegun was among a group of VOCAL-NY activists who showed up at the Y to demand more affordable housing units for the homeless.

Specifically, they asked that the mayor provide at least 30,000 extra units.

“Why won’t you commit more housing for homeless New Yorkers Mayor de Blasio?” demanded one advocate outside the gym. “Five percent is not adequate!”

“Mayor de Blasio may love working out, but his plan for housing homeless New Yorkers is just weak,” said Coalition for the Homeless policy director Giselle Routhier.

“This is simply unacceptable and perpetuates the ‘Tale of Two Cities’ he vowed to fix.”

It wasn’t difficult for the advocates to track down the mayor — he works out at the Y most mornings after being driven there from Gracie Mansion.

Emails released under court order show aides usually block out 3 hours most mornings for the mayor to be transported to the gym, do his exercises and be driven to City Hall or his next appointment.