A large blue rooster, which is about 15ft 5in tall, has been created by German artist Katharina Fritsch and will sit on the plinth for a period of 18 months.
Among those on hand to see the artwork – called Hahn/Cock – go on display was Mayor of London Boris Johnson, who commissioned it.
Mr Johnson said: ‘Katharina Fritsch commands tremendous respect internationally and her giant blue bird will provide a striking new focal as well as talking point for Londoners and tourists alike.’
The once vacant plinth has become a showcase for temporary artworks in recent years. PICTURE: Jonathan Brady/PA.