The pop star has also revealed a new partnership with CoverGirl that challenges the stigma around applying makeup in public.

Katy Perry released her new album Witness on Friday (June 9), and to celebrate, the pop superstar is nonstop live-streaming her life via her YouTube channel for a full weekend that has now expanded through Monday and will culminate in a live concert event. James Corden, Sia, Kacey Musgraves and many more will stop by throughout.

America Ferrera, RuPaul, Neil deGrasse Tyson and more will join in on the fun as well; see below for a full list of the weekend's featured guests and Perry's schedule.

The whole thing is being held in a house fashioned with 41 cameras for Big Brother-style live filming of her every move throughout all nine of its rooms. In expanding the live stream to Monday, Perry will keep the cameras rolling leading up to and through a live concert beginning at 4 p.m. PT in Los Angeles for just 1,000 fans to witness in person and the world to watch online.

As well, Perry has revealed exclusively to Billboard that she and CoverGirl are partnering to launch a new initiative called #projectPDA (Public Display of Application), which challenges the stigma of applying makeup in public. The campaign is intended to support people applying whatever type of makeup they want, whenever, however and wherever they want, CoverGirl SVP Ukonwa Ojo told Billboard.

This is the latest partnership between Perry and CoverGirl, including the brand sponsoring her live stream.

"As an innovator in the beauty space, CoverGirl was eager to partner with YouTube for its first-ever live stream show. It is a totally new and different way to engage with fan communities on the platform, which has deep relationships with beauty lovers -- making it a perfect fit for the brand," said Ojo. "We love that Katy is a strong female voice that represents freedom of expression.... Having Katy livestream her makeup routine on a global scale with YouTube is the ultimate statement about not needing to hide your makeup choices."

"Katy Perry Live: Witness World Wide" special guest appearances:

Neil deGrasse Tyson - joining Katy for a science conversation at 6:30 p.m. PT

Sia, Mia Moretti, Dita Von Teese -- sitting with Katy and other empowering females for a 'Rose & Thorn' on Friday at 8:30 p.m. PT

Arianna Huffington -- podcast chatting with Katy on Saturday at 3:30 p.m. PT

America Ferrera -- having a "moment" with a top celebrity chef Roy Choi for her organization, Harness, followed by co-hosting a dinner with Katy for Gavin Grimm and other special guests on Saturday at 7:30 p.m. PT

James Corden -- they'll be all over the house singing, laughing, eating on Sunday at 10 a.m. PT

RuPaul -- chit chat over lite bites with Katy on Sunday at 1 p.m. PT

Michael Ian Black -- whose podcast is How To Be Amazing with Michael Ian Black, will be chatting with Katy on Sunday at 5 p.m. PT.

Kacey Musgraves -- Kacey and Katy will teach fans how to play Kacey's "Follow Your Arrow" at Sunday at 6 p.m. PT. They will also do a moment for MusiCares

Gigi Gorgeous -- discussing her YouTube Red documentary This is Everything: Gigi Gorgeous with Katy on Sunday at 10 p.m. PT

Caitlyn Jenner, Amanda Seales, Margaret Cho and more will also be making appearances throughout the extended multi-day event.