In the version of this Letter originally published, in Fig. 2b, the label on the y axis should have been 'mΩ'. On page 1, the end of the second paragraph should have read “Now the existence of the topological surface states has been established it is time to study the interaction with other materials. Efforts have been made to contact a topological insulator to a superconductor in the search for the Majorana fermion and supercurrents have been reported22, 23. In this Letter, we report the observation of the two hallmarks of the Josephson effect: a Fraunhofer-like magnetic field modulation of the critical current and the appearance of Shapiro steps on microwave irradiation, resulting from the d.c. and a.c. Josephson effects, respectively. We demonstrate the existence of a Josephson supercurrent in the surface state of the topological insulator Bi2Te3.” These errors have been corrected in the HTML and PDF versions.