After being accused of using makeup to draw on a toned six pack of abs, Britney Spears has decided to open up about her stringent workout regimen, providing insight on just how she maintains her physique.

Last month, fans and critics questioned if the singer used contouring makeup on her stomach after she uploaded a photo of herself in a dress rehearsal for her new "Piece of Me" show in Las Vegas.  

"I see the spray tan marks from the abs," wrote one fan under the photo, while another commented, "Ur Abs are so fake! [sic]."

Another user wrote: "Oh my gosh. If having a nice body was really that important to you, you should be working out not painting them on!"

In response, the 32-year-old mother of two revealed that she does 90-minute yoga sessions and cardio workouts three times a week in an interview with Shape magazine.

"I'm doing 90 minutes of yoga twice a week in addition to a lot of cardio - hour-long sessions three times a week with my trainer, Tony Martinez," said the "Toxic" singer.

"Sometimes we focus on the core or relaxation, but other times I just kick her butt!" she continued, added that these moves help strengthen her core and sculpt her shoulders.

She also says that her on-stage dance routines have obviously helped add to her fitness plan. Plus, she says that she has been working very hard with new choreographers.

"This year I have new choreographers," she explained. "They're fresh and upcoming guys so their stuff is really hard. It's more rewarding after you perform something that's really hard to do rather than something that you just throw together."

Spears has credited yoga with changing her body for the better in the past, reports the Daily Mail.