Justin, 32, showed he was enjoying taking in all the sights and landmarks of London tweeting: "Look, kids!! There's Big Ben..! And, there's Parliament!"
Justin also treated his fans to a sneak preview of his new single today, taken from his follow up album to The 20/20 Experience, posting a clip on his YouTube channel.
Justin will be headlining Friday night at Wireless and then teaming up with none other than Jay-Z on Sunday night.
And with rumours Jay-Z's wife Beyonce might be making a guest appearance, it'd be rude to miss it.
Joined by Rita Ora, Emeli Sande, Calvin Harris and Will.i.am, the inner-city festival has got itself a new home this year, at a rather cool venue: the Queen Elizabeth Olympic Park in London.
But if you weren't lucky enough to blag now sold out tickets, get yourself into the festival spirit (perhaps stick your wellies on, and put up a tent in the garden?) by downloading our free playlist here, featuring all the biggest acts and their hottest tracks set to be performed over the weekend live from the festival.
And be sure to check out Reveal.co.uk for all the live reviews and juiciest gossip backstage direct from the festival.