updated 04/09/2012 AT 8:00 AM ET
•originally published 04/09/2012 AT 8:15 AM ET
The singer and actress, 30, is on the witness list and, once testimony begins, is expected to appear regularly at the trial of William Balfour, her former brother-in-law, which begins Monday in Chicago with jury selection, CNN reports.
Balfour was estranged from wife Julia – Jennifer’s sister – at the time of the killings. He is charged with fatally shooting Hudson’s brother Jason, her mother Darnell Donerson, and Julia’s 7-year-old son Julian King, allegedly in a jealous rage over what he thought was another man in Julia’s life.