AceShowbiz -

Taylor Swift turned heads at the iHeartRadio Music Awards on Sunday, April 3 and that's probably because the "Blank Space" singer showed a bigger butt. Following her appearance, many people accused her of having butt implants, but it's not the case after all.

A source close to Calvin Harris' girlfriend talked to HollywoodLife.com to set the record straight, clarifying that Taylor's impressive butt was a result of her hard work and sweat. "Taylor has a great new butt that she has been working hard for. Taylor's boyfriend Calvin is a workout fiend and so she has been doing her best to keep up with his high standards for health and fitness," the source explained.

The insider then said that the 26-year-old singer worked out really hard to keep her body healthy, and probably to make her backside tight. "Taylor has been exercising five days a week at Body By Simone, a group fitness dance studio in West Hollywood named after owner Simone De La Rue," the insider said.

"The hour-long classes combine dance, cardio and aerobics with great music and positive energy. Each class focuses on different body parts, like hips, thighs and buns, or abs, as well as over-all health and fitness," the source added.

The source went on claiming that a lot of celebrities like Selena Gomez, Jennifer Garner, Rosie Huntington-Whiteley, Chrissy Teigen and John Legend also attended the class. "Taylor has even shared her secret with Selena Gomez as the two of them have been spotted there a few times together," the source continued.