Von Bourbon's raunchy routine involved her stripping on stage to only her underwear, a corset and nipple tassels, while her breasts were obscured by gold stars. Her performance was aired before the 9pm watershed.
Ofcom is checking whether the episode broke the broadcasting code's duty to protect children from "material that is unsuitable for them". ITV has defended the incident, describing it as "suitably inexplicit".
A total of 70 complaints were made about the performance, which aired at 8.20pm on ITV1 on March 31. It was broadcast twice more before the watershed on ITV2.
ITV commented: "BGT celebrates variety and showcases a wide range of different acts. Mindful of our family audience, Beatrix's stylised burlesque performance was carefully edited to ensure it was suitably inexplicit."
Von Bourbon, a professional model and dancer, is expected to feature in the live semi-final stages of Britain's Got Talent after getting four yes votes from Simon Cowell and the other judges.
Britain's Got Talent continues on Saturday at 8.30pm on ITV1.
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