The 24-year-old will be joining the fans at the Hard Rock Calling festival in London's Hyde Park to watch bands such as The Killers and Bon Jovi.
She was recently at the centre of a kidnap and murder plot and the two men involved have since been arrested.
A source said to UK newspaper Daily Star: 'Joss has been through a hard time but she's not letting it get to her. She's really chilled out and just wants to get on with life as normal.
'Music is her life and she feels at home at festivals. She can't wait to let her hair down, have some fun and let off steam.'