The trio will play sold out shows across the next week as part of their Night + Day Festival.
Curated by members Jamie xx, Romy Croft and Oliver Sim, it is a celebration of their favourite local artists and communities.
They originally announced just three shows at the Brixton Academy but following a huge demand it was extended to seven in total.
This month they have also played sold out gigs in cities including Manchester and Nottingham, with a show in Cardiff lined up.
The group recently returned with third studio album "I See You", which marked their first release in five years.
It received critical acclaim and topped the UK albums chart as well as reaching number two in the US.
They also released their video for "Say Something Loving" on the same day as the festival kicked off.
The video which celebrates all love was also filmed across London, they said:"We wanted to celebrate our home town and revisit some of the places that reminds us of our friendship when we were growing up."
Who's the support act?
The xx will be joined by different artists and collaborators across the festivals run so it's likely that there'll be a different support act each night.
The first night (March 8) saw support from Joy Orbison and singer-songwriter and producer Sampha.
He has worked with artists including Solange, Kanye West and Katy B, is set to play Lovebox Festival this summer and recently released debut album "Process".
The second night (March 9) will see support from Ben UFO and Dillon Work who'll play back to back sets and then singer-songwriter Kelela.
Support act lineup:
9 March - Kelela / Ben UFO and Beatrice Dillon (b2b)
10 March - Robyn / Benji B
11 March - Francis and the Lights / Floating Points (DJ set)
13 March - Cat Power / Jehnny Beth / SIREN DJs
14 March - The London Contemporary Orchestra Performs Mica Levi / Daniel Brandt (DJ set)
15 March - Floating Points / Gilles Peterson
After party lineup:
8th March – Trouble Vision @ Corsica Studios – Line up TBA
9th March – Deviation @ The Prince of Wales – featuring Sampha (DJ set), Benji B & Judah, Secret Special Guest DJ Set
11th March – Robyn & Mr Tophat @ Phonox - featuring Robyn & Mr Tophat – DJ set, Haai and more TBC
14th March – Brother May, Coby Sey, and Mica Levi presents Curl @ Block 336
Are there any tickets?
Extra tickets for Jamie xx's solo gig on Sunday March 12 are available through Ticketweb.
The shows are completely sold out, but you can set a notification to your phone via Twickets which will let you know if anyone is selling them at face value.
What merch is one sale?
It looks like the merchandise features the group's "X" logo, a lot of black, and t-shirts with the tour dates printed on.
Plus there's a long sleeved "I See You" t-shirt which the band have been posting on their social media account:
What's the setlist?
The first of eight shows at the O2 Academy saw them perform the following the setlist:
Say Something Loving
Brave for You
I Dare You
A Violent Noise
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