LONDON — Facing the unpleasant prospect of being represented by a pair of empty chairs and a period of silence at a parliamentary committee hearing on phone hacking next week, Rupert Murdoch, the chairman of the News Corporation, and his son James reversed themselves on Thursday and said that yes, they would testify at the hearing after all.

The select committee on culture, media and sport will now have the chance to interrogate not only the two Murdochs but also Rebekah Brooks, chief executive of News International, the company’s British newspaper subsidiary. Ms. Brooks had agreed from the outset to testify.

Word that the Murdochs had shifted course came as one of several other moves by the News Corporation on Thursday that signaled the company was adopting a more assertive strategy to deflect the condemnation being hurled its way. It brought on outside public relations help for the crisis, hired a prominent white-collar defense lawyer and was said to be planning to run full-page apology advertisements in newspapers across Britain.

The elder Mr. Murdoch made his first extended comments on the matter, phoning a reporter at The Wall Street Journal, which he owns, to defend his company’s handling of the crisis. He said the matter had been handled “extremely well in every way possible,” and rejected claims that his son James had moved too slowly to address concerns about the hacking.