According to E! Online, Hudson was accompanied by her longtime fiancé David Otuga, who was there for moral support.
She told the courtroom that she repeatedly warned her sister, Juila, to never marry Balfour. "I told her over and over again to not marry him. We did not like how he treated her," she said.
Prosecutors then asked Hudson to recall her final meeting with her family. According to the Academy Award winner her family surprised her at her home a week before the murders. "It was my mother, my brother, my sister and my dog," she said. "I was so surprised. The whole family is here. That was the last time I saw them. Thank God I had the opportunity." Tearfully, she said they spent their time playing the piano.
If convicted, Balfour faces life in prison. He's pleaded not guilty to the charges.
The trial is expected to last about four weeks.