Miley Cyrus is back in action! 

The 21-year-old singer was beyond upset when an allergic reaction to antibiotics sent her to the hospital for several days.

The health issues caused her to cancel five U.S. concerts and postpone the European leg of her Bangerz tour. 

However, this Tuesday, the “Adore You” singer will be back at it at London’s O2 Arena. 

She could NOT be more excited - so how did she celebrate? A tweaking, booty-poppin’ session - which was caught on video and put on Instagram. 

#turndownforwhatLONDON #imbackmafuc*a #f*ckyeahLondon