Musician Bo Diddley is walking but struggling to communicate after suffering a stroke during a concert in the US, according to his manager.
Bo Diddley is regarded as one of the pioneers of rock 'n' roll
The 78-year-old appeared disorientated during a gig in Iowa. The musician has a history of hypertension and diabetes.
Speaking to Reuters from the hospital Margo Lewis said: "I'm truly encouraged by the way he is responding."
She added the stroke had left the star with no physical disability but had affected the left side of his brain.
Ms Lewis said it was too early to tell if he would recover enough to perform again.
"He is having a hard time understanding us. We're hopeful he can come back," Lewis said.
Doctors are hoping to move Diddley out of the intensive care unit in a couple of days.
Diddley first topped the US R&B charts with Bo Diddley in 1955. He was given a lifetime achievement Grammy in 1998.
He was due to play 11 dates across the UK at the beginning of June.
Diddley, with his black glasses and low-slung, rectangular guitar, has become an icon in the music industry with hits including Who Do You Love, Before You Accuse Me, Mona and I'm a Man.
He was inducted into the Rock and Roll Hall of Fame in 1987.