She adds with a grin: 'That's the tone that we want to strike.'
Streep is teaming up with Mamma Mia! director, Phyllida Lloyd, again on the movie, which started shooting at the beginning of the year.
The film is believed to follow Thatcher in the day leading up to the Falklands war in 1982.
Jim Broadbent plays her devoted husband Denis Thatcher while Richard E Grant has been cast as Michael Heseltine and Roger Allam stars as Gordon Reece.
Olivia Coleman plays Thatcher's daughter Carol with Anthony Head as Geoffrey Howe, Michael Pennington as Labour leader Michael Foot and Julian Wadham as Francis Pym.
margaret thatcher
margaret thatcher
margaret thatcher
margaret thatcher
margaret thatcher
