Rihanna recently delayed a trip to the UK to look after her grandmother

Rihanna has taken to Twitter to explain why she wasn't herself at a gig in Sweden on Saturday night.

Ri-Ri came under fire for giving a 'disgusting and shameful' performance on the day her grandmother Dolly passed away from cancer.

Fans were angry with the 24-year-old for arriving 45 minutes late to a gig in Borlange on 30 June and accused her of looking 'under the influence' and miming.

'Goodbye #grangranDOLLY get your beauty rest until I see you,' Tweets Rihanna, along with a series of photos of Dolly.

The singer recently delayed a trip to the UK by a week in order to spend time with her gran, who was being treated in a New York hospital.

Fans were quick to take to Twitter to console the Bajan star after she revealed the news and she later received a message from her ex-boyfriend Chris Brown's mother Joyce Hawkins.

'Angel may God be with you and your family in your time of sorrow. Love you angel,' Tweeted Joyce.

SEE PICTURES Celebrity hair style file: Rihanna>>

SEE PICTURES Rihanna's style file>>

SEE PICTURES Rihanna's rise to fame>>

Anna Duff