The Crown: Gillian Anderson Cast as Margaret Thatcher in Season 4 (Report) TVLineGillian Anderson Will Fill Your Iron Deficiency As The Crown’s Margaret Thatcher VultureGillian Anderson Is Going to Play Margaret Thatcher on The Crown JezebelGillian Anderson Set To Join ‘The Crown’ Season Four As Former British Prime Minister Margaret Thatcher DeciderThe Crown: Gillian Anderson cast as Margaret Thatcher on Netflix's hit series.