The model was due to meet the Umbrella hitmaker backstage after a recent gig in Los Angeles, but the star failed to show.
Huntington-Whiteley tells BBC Radio 1 host Nick Grimshaw, "I was standing there going, 'Oh my God, I'm going to meet Rihanna'. I stood there and 20 minutes went by, and as more time went by the more nervous I got. Then, after about three hours of waiting, I was like, 'I've had enough!'"
However, the Transformers: Dark of the Moon beauty has not lost hope and is still determined to befriend the singer, adding, "I'm really nervous to meet her now, I'm going to get starstruck and say something I'll regret. She's so cool."