The Chief Justice of the United States misread the oath of office during the inauguration of Barack Obama as President today.

John Roberts first interrupted the President-elect during the oath, then asked him to repeat: “I will execute the office of President to (sic) the United States faithfully…”

Obama, who has almost certainly practiced the oath, paused, aware that the wording was not that stipulated in the United States Constitution.

Article II Section I establishes the oath as: “I do solemnly swear (or affirm) that I will faithfully execute the office of President of the United States, and will to the best of my ability, preserve, protect and defend the Constitution of the United States.”

“That I will execute…” he began, only to be interrupted by Roberts, who was appointed to the Supreme Court by President Bush in 2005.

“Faithfully the office of president of the United States…” said Roberts, to which Obama responded “the office of president of the United States faithfully.”

The rest of the oath then proceeded without any mistakes.

Soul legend Aretha Franklin sang at the ceremony, which was watched by an estimated two million people packed along the National Mall in Washington DC.