The pair wowed bargain hunters by popping up outside Oxford Circus Tube station to perform new track Find Me during the impromptu session on Friday.
Dozens of shocked fans gathered to film the stunt and took to social media to discuss their amazement.
One Twitter user wrote: “When @TinieTempah randomly starts rapping #FindMe with @JakeBugg outside Oxford Circus. Prime views from the office.”
Others expressed their dismay at missing out.
Stephen added: “Tinie Tempah and Jake Bugg performing impromptu outside Oxford Circus tube station earlier..Grr I wanna be there.”
The pair were also spotted at St Pancras International as they made their way across the city.