Miliband, the youthful British foreign policy chief, is seeking to soften the tone of global relations after Britain became involved in wars in Iraq and Afghanistan.
"He will meet Angelina Jolie in New York for talks," a Miliband spokeswoman said, while speaking on condition of anonymity in line with ministry policy.
Further details on the planned content of the discussion weren't immediately available.
Miliband, who was Britain's first blogging Cabinet minister in his last role as environment chief, will launch a new blog Wednesday. He is encouraging key aides to follow his lead.
"The day when we communicated mainly by telegram are over," Miliband told the Evening Standard newspaper. "Communication has to be for the masses now, not just elites."
By David Stringer