Ariana Grande arrived in the UK Friday morning ... gearing up for her benefit concert Sunday to benefit victims of the Manchester terror attack.
The singer, who arrived with her parents and BF, Mac Miller, personally worked with her manager, Scooter Braun, to book the event, which will also feature Justin Bieber, Katy Perry, Coldplay, Miley Cyrus, Pharrell, Usher and Niall Horan.
Ariana will probably board her jet a second time shortly, to make the trek to Manchester.
The concert sold out in 6 minutes.