Legendary music artist Aretha Franklin is “gravely ill”, friends of the singer confirmed to US media Tuesday morning.

A source close to the singer was quoted by the Associated Press as saying the 76-year-old Franklin is “seriously ill,” but did not provide any additional details as to the severity or the cause of her illness.

Reporter Evrod Cassimy of the Local 4 news outlet in her home city of Detroit, wrote on Twitter: “I am so saddened to report that the Queen of Soul and my good friend, Aretha Franklin is gravely ill.

“I spoke with her family members this morning. She is asking for your prayers at this time.” He said he had been asked not to release information of her illness,” he posted.

People magazine quoted a longtime friend of Franklin’s as saying Franklin’s family have been warned that her death is ‘imminent”.

“She has been ill for a long time,” People quoted the friend as saying.

“She did not want people to know and she didn’t make it public.”

Franklin has faced bouts of ill-health since 2010, when she was diagnosed with pancreatic cancer, a family member told Detroit media.

She cancelled planned concerts earlier this year after she was ordered by her doctor to stay off the road and rest up.

Franklin was originally scheduled to perform on her 76th birthday in March in Newark, New Jersey, and at the New Orleans Jazz and Heritage Festival in April.

Last year, the icon announced her plans to retire, saying she would perform at “some select things”.

One of those select events was a gala for Elton John’s 25th anniversary of his AIDS foundation in November in New York City, where Franklin closed the event with a collection of songs including I Say a Little Prayer and Freeway.

Fans and friends of the soul music icon, including Mariah Carey and Missy Elliott, have offered prayers and well wishes.

Carey, who considers Franklin one of her biggest influences, wrote on Twitter that she is “praying for the Queen of Soul”.

Missy Elliott said that the public has to celebrate iconic artists before they die.

“So many (of them) have given us decades of Timeless music,” the rapper wrote on Twitter.

Mark Frost, Andy Cohen and Ciara also posted about Franklin, who is considered one of the greatest singers of all time and is known for hits such as Respect and (You Make Me Feel Like) A Natural Woman.

Abdul “Duke” Fakir, the lone surviving original member of the Four Tops, told the AP he and Franklin had been “very close” for decades and their most recent conversation was about a week ago by phone.

Fakir said they talked after Franklin had stopped by his Detroit house when he wasn’t there.

“She was telling me she rides around the city every now and then – she talks about how beautiful it is again,” Fakir said.

“We were reminiscing about how blessed we were – only a couple, two of us are around from that era. We were just kind of reminiscing about the good times we had.”

Fakir, who calls Franklin “baby sis” because he’s older than she is by six years, said despite her health troubles “she was talking about the future”.

“She talked about this great, big special she was going to have in New York, with all her great friends performing,” he said.

“It made me feel good as well – she was still hoping and wishing and dreaming as we do in this business.”

-with agencies