A groundswell of prayers has been piling up for Oscar winner Jennifer Hudson following the deaths of her mother, brother and nephew late last month.

"It is almost inconceivable to imagine the burden she is now carrying," commented Guideposts magazine Editor-in-Chief Edward Grinnan, whose publication features Hudson on the cover of its November issue.

"We know that Jennifer is a woman of great faith and what she needs now most is our prayers."

On Monday, hundreds of mourners attended a private funeral service for Hudson's slain relatives at the massive Apostolic Church of God in South Side Chicago.

City mayor Richard Daley and the Rev Jesse Jackson were among those who spoke at the three-hour service for Darnell Hudson Donerson, 57, Jason Hudson, 29, and Julian King, 7, who were found shot dead late last month.

Monday's services followed a public memorial held Sunday at Pleasant Gift Memorial Baptist Church, where Hudson sang in her childhood.

Hudson has often credited her rise to fame to her upbringing in the impoverished neighbourhood on Chicago's South Side where she went to grade school and sang in church.

The Oscar-winning actress and singer rose to fame after becoming a finalist in the 2004 season of "American Idol" and solidified her stardom with an Academy Award in 2007 for her film debut, a supporting role in "Dreamgirls".

Despite her celebrity status, Hudson has maintained her humility, "stand[ing] in line with everybody else."

"[W]hen I go home to my mum I'm just Jennifer," she tells reporters.

Guidepost's Grinnan, whose publication photographed and interviewed Hudson earlier this autumn in her hometown of Chicago, further noted Hudson as "a wonderful person to work with - upbeat, energised, exciting and surprisingly even-keeled for someone to whom success and fame had come so young".

"She spoke movingly of her extraordinarily close relationship with her family and that is what we focused her story on," he stated. "Her family nurtured her great talents and sustained her during difficult times."

Since the tragedy, Grinnan says the cover story on Hudson has received an "overwhelming response".

"In the past few days, there has been an unprecedented outpouring of prayers and support for Jennifer and her family posted at Guideposts.com," he reported.

"All of us at Guideposts send our prayers and condolences to Jennifer," Grinnan added.

According to reports, no one has yet been charged in the shootings of Hudson's family members, although authorities have called her sister's estranged husband, 27-year-old William Balfour, a "person of interest".

Balfour, who had served seven years for a 1999 attempted murder and vehicular hijacking conviction, is currently in custody on a parole violation.

His mother, Michelle Balfour of Chicago, meanwhile has denied that her son had anything to do with the deaths.

"All I want is for my son to come home," she told reporters after offering her condolences to the Hudson family.