The Twitter message came after an appeal by the brother of the Irish student, who was injured in the Berkeley tragedy.

Her brother Daragh had asked JK Rowling to contact his sister because she had been listening to Harry Potter audio books while recovering in hospital.

Posting on her official Twitter account, the author wrote: “Wishing Clodagh Cogley a very speedy recovery and sending much love to her, her friends and family xxx”.

Wishing Clodagh Cogley a very speedy recovery and sending much love to her, her friends and family xxx

— J.K. Rowling (@jk_rowling) June 19, 2015

Ms Cogley is the granddaughter of legendary RTE rugby commentator Fred Cogley. The 21-year-old was one of the seven seriously injured following the balcony collapse in Berkeley that killed six other Irish students.

Ashley Donohoe (22), Olivia Burke (21), Eoghan Culligan (21), Niccolai Schuster (21), Lorcan Miller (21) and Eimear Walsh (21) died when the fourth-floor balcony of an apartment complex collapsed.