Aretha Franklin knew she was seriously ill when she felt a crippling pain in her side.

The 68-year-old singer - who underwent surgery in December for an undisclosed complaint - revealed the pain she felt was so severe she could barely stand and immediately pulled out of her concert tour in order to receive treatment.

She told TV talk show host Wendy Williams: "That [pain in my side] was my first inkling that something was wrong, that something wasn't what it should be.

"The pain was so hard it nearly brought me to my knees. So I said, 'The concerts are over. I have to go find out what is wrong.'"

While it has been reported the 'Respect' singer is suffering from pancreatic cancer, she has refused to name the exact illness and would not be drawn further on details of her surgery.

When the talk show host said: "In December we all found out that you were having abdominal surgery", Aretha replied: "Hmm. Is that what you heard?"

Doctors told Aretha after her operation in December that she must recuperate for eight weeks, but she has previously revealed she "absolutely" plans to reschedule all of the tour dates she was forced to cancel when she fell ill.