Sheila Henry, mother of 7/7 victim Christian Small, has brought a civil claim against the News of the World over allegations that her phone was hacked, her solicitor Mark Lewis has said.
Her case will now be heard alongside those of actor Jude Law, MP Chris Bryant and three others, the BBC reported.
The High Court will decide which cases can go ahead.
The development came as MPs said they would recall James Murdoch, chief executive of News International, to appear before a parliamentary hearing over phone hacking claims.
The News Corp head's evidence to MPs had been questioned by News of the World's former legal manager and editor, Tom Crone and Colin Myler, during a session last week.
Huffpost UK understands that Les Hinton, the former executive chairman of News International, has also been recalled. He told parliament two years ago that he believed only one reporter, Clive Goodman, had written stories based on hacked voicemails.