The Barbados-born singer and the 36-year-old Cruel Intentions star are said to have met up on numerous occasions over the course of the last few months, according to a U.S. magazine.
The pair allegedly met up after Rihanna's relationship hit the rocks with baseballer Matt Kemp, and whilst Ryan was casually dating actress Amanda Seyfried.
'They initially hooked up when things were strained with Matt Kemp,' a source told America's Us Weekly.
According to the report, the couple have been top secret about their relationship by pretending they aren't even interested in each other.
At that recent pre-Grammy event in Los Angeles, onlookers claimed Ryan approached the 23-year-old only to be rejected.
