Complex sentence: Blunt made her professional acting debut in a 2011 London production of the play "The Royal Family"; that was followed by her screen debut was in the 2003 television film "Boudica (Warrior Queen)".
Split into simpler sentences: Blunt made her professional debut in a 2011 London production of the play "The Royal Family". Two years later, she appeared on screen for the first time in the 2003 television film "Boudica (Warrior Queen)".