What led to Mel B breaking her ribs and 'severing' her hand

Mel B’s recent injuries are the result of a fall down stairs.

After saying that she was suffering from a severed hand and broken ribs Monday morning on Instagram, more details are coming to light about how the 43-year-old Spice Girls singer’s injuries occurred.

ET has learned that Mel was staying at a friend’s house in London, England, over the weekend and, when she woke up and decided to go downstairs, she fell down a narrow staircase. Her friend took her to the hospital where doctors determined she needed surgery, which she has already undergone.

Mel was scheduled to fly back to Los Angeles, California, on Sunday, but is still recovering in London. She was supposed to be in L.A. on Monday to take her court-ordered drug and alcohol test.

Though she won’t be in L.A. for the Monday test, ET has learned that, when she arrived at the hospital in London, doctors performed a drug and alcohol test, of which all of the results came back negative. Her rep says the drug and alcohol test at the hospital was mandatory per the doctors, not a part of her court-ordered test that she was supposed to take on Monday.

Her rep previously told ET that the singer has tested negative on her last 14 drug and alcohol tests. Her rep insists to ET that neither drugs nor alcohol played a role in Mel’s fall.

As a result of the tumble, Mel canceled a New York signing of her book, Brutally Honest, which she said would be rescheduled. Additionally, on Monday’s Today, Kathie Lee Gifford and Hoda Kotb revealed that Mel’s scheduled co-hosting gig of the morning show’s fourth hour on Tuesday's episode was canceled before wishing her the best.

Mel revealed her injuries in an Instagram post Monday morning, where she thanked the hospital staff and her fans for their support.

“For now my right arm/hand is all stitched up and I’m trying to keep still to heal my broken ribs, ohhh the pain,” she wrote in part. “But I’m in super safe hands with the care of everyone here at the hospital!!!!! Thank you all for understanding, I love you all.”

In a second Instagram post, the singer showed off her hospital visitors -- the Spice Girls themselves! In the gif, Mel is lying in the hospital bed, while Melanie C, Geri Halliwell and Emma Bunton surround her and make cute faces for the camera.

"When your besties show up to the hospital with hugs and laughter and A LOT of love, ahhhh I love my spice girls yipppeee #friendship #family #spicegirls," Mel captioned the sweet post.

The injuries come in the midst of a busy time for the singer, who recently released her memoir, Brutally Honest, and is set to tour with the Spice Girls next year.