The 18-year-old singer pulled up next to a group of supporters waiting outside the Tonight Show with Jay Leno studio on Wednesday (June 27), where Bieber was due to film an appearance.
Accompanied by a guitarist, Bieber then treated fans to a stripped-back rendition of his global hit before driving off again, leaving them screaming behind.
The surprise came little over a week after the 'Baby' singer was filmed blasting his fans for being "impatient" and "not very respectful" while he waited at an airport for girlfriend Selena Gomez.
© PA Images / John Shearer/AP
Bieber confirmed this week that 'As Long As You Love Me' will be the second single released from his third studio album Believe.
The LP beat Cheryl Cole's A Million Lights to the top of the UK album chart and has reached number one in nine other countries.
