Jay Z, Chris Martin and Entourage Take London Underground to Concert, Surprise Fans

Jay Z, Chris Martin of Coldplay and producer Timbaland were spotted on the London underground Saturday while heading to a concert at the O2 Arena. The rapper and his entourage of 10 or so people were heading to his show, which was a major stop on the Magna Carta world tour.

Jay Z was joined by Chris Martin, Timbaland, CC Sabathia, Robinson Cano and about 10 others on the London subway— also called the Tube— on the Jubilee Line to North Greenwich. Fans of the rapper were starstruck and surprised at seeing him face-to-face, as many of them were heading to his Magna Carta concert as well.

"What a riot… Just met Jay Z on the tube in London," Jamie Robb tweeted.

"Coming off the tube and I see Jay Z casually walking up the escalator next to me… EVERYONE GOES NUTS!!" another passenger, Elias, posted on the microblogging network.

After the show, the rapper and his group of famous friends headed to the London Shoreditch for the Cognac D'Usse after party. He also performed at the O2 Arena on Monday, and will head toward mainland Europe next.

This isn't the first time Jay Z has made waves while taking public transportation. In December, the 43-year-old rapper rode the subway to Barclay's Center in Brooklyn for one of his concerts. He ended up sitting next to 67-year-old visual artist Ellen Grossman, and their interaction was filmed for his documentary "Where I'm From."

"Are you famous?" she initially asked, noticing the large crowd on the car and the cameras.

"Not very famous— you don't know me," Jay Z, whose real name is Shawn Carter, told her over the din. Although he initially introduced himself as only "Jay," once he said "Jay Z," it clicked.

"Oh you're Jay Z? I know about Jay Z," said the woman.