Did James Corden actually write his apology, or did he learn to write in “American”?

The Daily Mirror

The Daily Mirror points out that Corden, in his Twitter apology for his Harvey Weinstein jokes, spelled “behavior” the American way and not the British way of “behaviour.” The Daily Mail asks: “Did Corden write his apology? Or was it his PR, or a US phone spell check? Or did he not care enough to do it himself?”