Reunited rock act Blur adopted an unusual way of premiering their new songs as they performed them in a live show via Twitter.
The quartet sent a link to a live stream as they performed from a balcony at a secret location to unveil the first of the songs, Under The Westway.
The band, who last reunited for gigs in 2009, have been working on at least two new tracks as they prepare for a headline show in August.
Throughout the day the group teased fans by posting images online as their equipment was set up, as well as a series of slogans.
They included "the flash of a blade is one less getting paid", "it's smoke and mirrors until the autocue starts" and "I stood watching comets on their lonesome trails".
At 6.16pm local time the band burst into life with a slow, ringing piano and a whining guitar with a track which hinted at the band's sound in the early 1990s, with a hint of early 70s David Bowie.
The group - fronted by Damon Albarn, who has gone on to set up numerous side projects including Gorillaz - will be performing in Hyde Park in August in a show which coincides with the Olympic closing ceremony.
In a question and answer session via Twitter, the band confirmed the concert would be a career-spanning set "including the new tracks''.
Asked how it felt to be playing together again guitarist Graham Coxon said: "Like a silk smoking jacket.''
And in response to one fan who said she was wiping away tears, bass player Alex James responded: "I feel quite emotional too."
The band returned an hour later to perform their second track The Puritan, which was pacier and more rough-and-ready than the earlier song.
Albarn, playing a half-size acoustic guitar, was grinning from ear to ear by the time the track wound up.
James could be seen bouncing around wearing shorts on the damp rooftop from which fans could get a view across west London, with a view of the Westway flyover in the background.
The two Blur tracks were the first newly-aired material since the release of a limited edition seven-inch single for Record Store Day in 2010.