Following the confirmation that Chase & Status will headline the event at London's Clapham Common on Saturday, August 25, Skrillex tops the bill on Sunday, August 26.
"The epicentre for Skrillex's colossal summer activities, it can now be announced that South West Four will play host to his EXCLUSIVE London festival performance for 2012," organisers confirmed.
They added that the performance would be Skrillex's largest ever show in London and his biggest headline set in the UK this year.
Pre-sale tickets for the Sunday at South West Four go on sale this Monday, March 5 at 9am. Super-saver weekend tickets are available now and are priced at £85 plus fees.
Remaining tickets go on general sale on Wednesday, March 7.
Skrillex has recently been romantically linked to singer-songwriter Ellie Goulding.
> 'SSX' track list features Run-DMC, Skrillex, Wretch 32, Nero
Watch the Skrillex 'Bangarang' music video below: