Lady Gaga shows off her number in a rehearsal video.

Lady Gaga shows off her number in a rehearsal video.

Lady Gaga, outdone on stage for the first time last week by Miley Cyrus, is planning to step up her sexual impact when she hits the stage for the iTunes Festival on Sunday (Sept. 1) in London.

Gaga, real name Stefani Germanotta, released some rehearsal footage on video today (Aug. 31).

She was wearing hip-hugging black tights and a black bra-top with her dark hair pulled back in a loose bun. Gaga will open the month-long festival and apparently plans to one-up Miley with her sexy act.

The 27-year-old “Applause” singer was the opening act of the MTV Music Video Awards and usually steals the show with her sexy performances. She went through three costume changes during her number and ended in a tiny seashell bikini that didn’t leave much to the imagination.

Her skimpy outfit was a surprise shock ending to her number, but Miley quickly overshadowed her. She hit the stage for a medley of her song “We Can’t Stop” and Robin Thicke’s hot summer song “Blurred Lines.” Miley was beyond sexy as she vamped, sassed, wagged her tongue and twerked on stage.

Miley’s performance touched off a frenzied reaction that went on for days. Gaga hardly got a mention, even though her act was almost just as racy. Gaga later defended Cyrus’s performance.

“Generally, people need to lighten up about pop music, it’s about entertainment. It is here to make you smile and make you happy,” she told London’s Sun newspaper.

She tweaked critics, nothing that “especially in America there is an excessive dragging of female artists.”

In her rehearsal video, her backup dancers writhed and swayed around her as she belted out her song. Last week, she displayed a snippet from her new song Swing.

Check out her performance below, her photos and follow TheImproper on Twitter for the latest Lady Gaga updates. If you’re a Lady Gaga fan retweet this story to show your support!!!