Question: who does the voice of fiona in shrek
[{'answer': 'Cameron Diaz', 'provenance': [{'wikipedia_id': '2050495', 'title': 'Princess Fiona', 'start_paragraph_id': 2, 'start_character': 397, 'end_paragraph_id': 2, 'end_character': 409, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]