Demi Lovato is "itching" to get back to Kenya.

The 'Heart Attack' singer flew to Africa on August 14 with Canadian-based charity Free The Children, which works internationally to empower and enable youth to be agents of change, and has revealed it was a life changing experience.

The 'X Factor' USA judge, who previously sought treatment in rehab for an eating and self-harming disorder, tweeted: "Just had the most amazing week of my entire life. Words and photos will never be able to describe how incredible this was..

"Already itching to get back!!! Thank you so much @freethechildren for solidifying the importance of my recovery and changing my life."

She added: "This place is absolutely incredible. I'm so in love with Kenya. I'm so sad I'm leaving...."

Demi celebrated her 21st birthday in the country on Tuesday (20.08.13) with her mother Dianna and four close friends.

They marked the occasion by enjoying a safari tour as well as a hot air balloon ride.

She tweeted: "This trip has been such an amazing experience. Yesterday was the best birthday of my entire life!!!"

She also bonded with the local children and received a unique gift.

She said: "Btw (By the way)... No big deal or anything but... One of Maasai communities gave me a GOAT for my birthday!!!!!! ...I named him billy."

The singer is now back in the US, where she is preparing for her performance at the Festival People En Espanol in San Antonio, Texas, on Sept. 1.