When Rupert Murdoch fired off a tweet Saturday about some "scumbag celebrities" he didn't mean "any particular people," the Newscorp boss later tweeted.

"I never referred to any particular people, just some 'dodgy' self promoting celebrities," he said, adding the words: "Repeat apology for language."

Murdoch found himself in trouble on Twitter over the weekend for apparently referring to Welsh singer Charlotte Church, actor Hugh Grant and television presenter Jacqui Hames as "scumbags" after they met with British Prime Minister David Cameron to discuss the potential reform of Britain's media laws.

It's not clear whether Grant attended the meeting, but on October 9 British media reported that Church and Hames met Cameron during the Conservative Party conference in Birmingham, England.

The meeting came weeks before the Leveson Inquiry is due to report its findings on the culture, practices and ethics of the British press and its relationship with the public, police and politicians.

The inquiry heard from Murdoch and former British Prime Ministers, Tony Blair and Gordon Brown, along with celebrities, sports stars and even the families of murder victims who claimed that their phones had been hacked by employees of the now defunct, Murdoch-owned newspaper, "News of the World" (NOTW).

On Saturday, the media baron tweeted: "Told UK's Cameron receiving scumbag celebrities pushing for even more privacy laws. Trust the toffs! Transparency under attack. Bad."

The missive prompted this retort from Church: "@rupertmurdoch It would be decent to withdraw & apologise for -- calling me, @CharlotteChurch and@jacquihames*scumbags*."

Hames, a former detective-turned TV presenter who fronted the British crime-fighting program Crimewatch, also demanded an apology, after earlier tweeting: "I've been called worse, but admittedly not by CEO of large multinational corp."

Both women, along with actor Hugh Grant -- who is not on Twitter -- have been vocal supporters of Hacked Off, a pressure group that's fighting for "a better press that is answerable to the public it is supposed to serve," according to its website.

They were among 60 signatories to an open letter on October 6 that called on Cameron to keep an open mind when considering Leveson's recommendations on press reforms.

It followed British media reports that suggested the British prime minister might be leaning towards self-regulation.

Actor Grant told the BBC's "The Andrew Marr Show" on October 7 that campaigners had been concerned to hear "weird rumblings" from government ministers.

"We get these odd articles in The Times saying the government ... close sources or reliable sources at No. 10 say the government has already decided not even to listen to Leveson before it's published and to go with more, yet more self-regulation of the press," Grant said.

Cameron appeared on the same program to say he didn't want to preempt Leveson's recommendations, but added, "we don't want heavy-handed state intervention. We've got to have a free press."

Lord Justice Leveson is expected to hand down his findings in early November.

Months of evidence included the high-profile grilling of Murdoch, who told the inquiry he didn't believe in journalists using phone hacking or private detectives, calling it "a lazy way of reporters doing their job."

He painted News Corporation, which owns the Sun and the Times in London, as well as The Wall Street Journal, New York Post and Fox News, as a victim of the cover-up. "Someone took charge of a cover-up, which we were victim to and I regret," he said.

Last year, at one of two UK parliamentary inquiries into the hacking scandal, Murdoch said his appearance was "the most humble day of my life."

A number of former News Corp. staff have been arrested and charged with conspiracy to intercept communications including former NOTW editor Rebekah Brooks who's scheduled to face trial next year.