The FBI is planning to contact Jude Law as part of its investigation into whether News of the World journalists hacked phones in the US, after the actor claimed his voicemail was accessed while he was in New York.
The development suggests the US authorities are widening their investigations into the hacking scandal, threatening larger legal penalties for any journalists involved and for Rupert Murdoch's US-based media empire.
The FBI opened its inquiry after pressure from politicians last week, when it was first alleged that NOTW journalists tried to access the phones of victims of the 9/11 terrorist attacks. News International, owner of the now closed newspaper, denies all the accusations that there was hacking on US soil.
Mr Law made his claims last week, saying that he and his personal assistant had their phones hacked when they arrived in the US for the filming of I Heart Huckabees in 2003.
The allegation is particularly dangerous for News International because it is the first specific claim that phone hacking was carried out in the US, where Mr Law's mobile would have been using an American phone network and therefore subject to US laws.
Mr Law is also suing News International, alleging that another Murdoch paper, The Sun, hacked into his phone in the UK in 2005 and 2006.
News Corp, News International's parent company, owns several major media businesses in the US, including the right-wing cable channel Fox News and The Wall Street Journal . Democratic politicians have threatened Congressional hearings into whether the hacking scandal in the UK extended to US soil and to other organisations in the Murdoch empire.
News Corp has hired prominent attorneys to help defend itself in the US. The Department of Justice is examining whether paying bribes to police in the UK might breach a tough anti-corruption law, which outlaws any US company from paying bribes to foreign officials.
The Securities and Exchange Commission, which regulates companies' communications with shareholders, is also under pressure to examine whether News Corp should have revealed more information about the scandal in its UK arm.