Yellen will appear at 1 pm ET (1700 GMT)

Yellen speaks at the top of the hour but don't expect headlines at the top of the hour. There is no lockup or pre-released text of her speech. In fact, there's no real speech at all.

Yellen is in London at forum and today's event is a conversation with Nicolas Stern, who is the President of the British Academy and an economics professor. The topic is 'global economic issues.'

" Stern and Federal Reserve Board Chair Janet Yellen will have a wide-ranging discussion about global economic issues," the billing says.

Along with the conversation, she will also take questions from the audience.

Expect the event to last and hour or 75 minutes. I'll look out for a live stream.