Rebekah Brooks and her husband, Charlie, will be told later if they are to be charged with perverting the course of justice.
A solicitor for the couple said they would be informed shortly before 10:00 BST, when they answer police bail.
An announcement on the former News International chief executive and her husband would then be made public.
The BBC understands five others will also be told whether they are to face charges over the phone-hacking scandal.
Mrs Brooks appeared before Lord Justice Leveson at his inquiry into media ethics on Friday.
The former Sun and News of the World (NoW) editor was questioned for more than five hours - about her relationship with politicians including David Cameron and former prime ministers Tony Blair and Gordon Brown - as well as decisions taken by her papers when she was editor.
Mrs Brooks was the NoW editor when voicemails on murdered schoolgirl Milly Dowler's mobile phone were intercepted.
She was arrested on 13 March on suspicion of conspiring to pervert the course of justice as part of Operation Weeting, the Metropolitan Police's investigation into phone-hacking.
Mrs Brooks had first been arrested last July on suspicion of conspiring to intercept communications and corruption, before being released on police bail.
Now phone hacking
The hacking of phones by the NoW first came to light in 2006 when the tabloid's then royal editor Clive Goodman, and private investigator Glenn Mulcaire were accused of illegally accessing the voicemails of royal aides.
They were jailed in 2007 - for four months and seven months respectively - after admitting the practice.
The NoW was closed in July 2011 after mounting evidence that phone hacking to find stories was more widespread. At least 50 claims against the NoW have now been settled.
Scotland Yard is conducting three investigations relating to the phone-hacking scandal.
Operation Weeting is looking into allegations of hacking by the NoW into private voicemails, Operation Elveden is examining allegations that journalists from News International made "inappropriate" payments to police, and Operation Tuleta is investigating computer hacking.
Meanwhile, Lord Justice Leveson's inquiry has been examining relations between the press, politicians and police, and the conduct of each.