VV Brown will be performing live as well as Kissy Sellout. Siouxsie Sioux is DJ'ing, as is Frankmusik, Dan from The Feeling, Jodie Harsh and Kris di Angelis.
To win the tickets just answer this one question:
How many double-decker buses could fit into The O2?
Email your answer to firstname.lastname@example.org - including your name and address. Please put 'Circus at Matter Competition' in the email subject line.
The competition closes on Friday 12 June at 6:00pm BST. Jodie Harsh will then pick the winner who will be notified by email. If there is no reply from the winner within 48 hours an alternative will be picked.
Tickets available from www.ticketweb.co.uk
Matter, the o2, Peninsula Square, London, SE10 ODY