The 23-year-old was reportedly given a book about Cockney rhyming slang and she hasn't been able to put it down since.
The We Found Love hitmaker been reading out the rhyming slang phrases in a Cockney accent and has been finding it amusing.
A source told British newspaper The Sun: 'Rihanna was given the book when she was last over and can't get enough of it.
'She's been reading phrases aloud in her best Cockney accent and finding it hilarious.
'Spending so much time in the UK has gone to her head, in a good way. She wouldn't have bothered trying to understand dialects before.'