Virgin Mobile has announced the lineup to their annual FreeFest.

The festival will take place at Merriweather Post Pavilion in Maryland on Sept 21st.

'Tickets on Free' (aka free tickets!) on August 9th at noon, but they do ask for a donation to go towards housing homeless youth.

The line up includes: Robin Thicke, Icona Pop, Vampire Weekend, The Avett Brothers, Pretty Lights, Kaskade, MGMT and City and Colour. See the full lineup here.

Image courtesy Virgin Mobile