Jean Dujardin won the Oscars 2012 in the category of Best actor in a leading role for his role in the The Artist. Christopher Plummer won the Oscars 2012 in the category of Best actor in a supporting role for his role in Beginners.
Meryl Streep won the Oscars 2012 in the category of Best actress in a leading role for her role in The Iron Lady. For the full list, check here.