The body of Qandeel Baloch was discovered on Saturday
Wasim Baloch confessed to murdering his sister and described it as an "honour killing".
"The police arrested Muhammad Wasim, brother of Qandeel Baloch, for killing his sister late on Saturday," Multan City police chief Azhar Akram said.
"Wasim confessed to his crime, saying he killed his sister for honour after her recent objectionable videos, mostly posted on Facebook."
Wasim said he drugged his sister before strangling her to death. "She was on the ground floor while our parents were asleep on the rooftop," he said. "It was around 10.45pm when I gave her a tablet [...] and then killed her."
For his part, Wasim told journalists at a press conference that he had "no regrets" over the murder, as his sister had brought "dishonour to the Baloch name", and described her actions as "intolerable".
He is due for a second hearing in court on Wednesday.
The social media outpouring after her death has been widespread.
#QandeelBaloch was larger than life, in your face, unapologetic about her ambitions and her womanhood. Goodbye, you crazy, beautiful woman— Feminism Matters™ (@WeNeedFeminlsm) July 17, 2016
Although Baloch received frequent threats, Al Jazeera report that she had "appealed to the interior ministry to provide her with security for protection" prior to her death.
Late on Friday, she posted a photo of herself to a social network saying "No Matter how many times i will be pushed down under,,But I m Fighter I will Bounce back.. # Qandeel #Baloch is "One Women Army".. #Qandeel #Baloch inspiration to those ladies who are treated badly and dominated by the society..I will Keep On Achieving and I know You will Keep On Hating."
Akram said that they would be seeking the "maximum punishment" for the killing.