The 24-year-old singer - who was spotted making a midnight visit to Ashton's house last week - did not try to hide her disgust when a journalist for British television network ITN quizzed her about the rumoured romance.
At a London press conference for Rihanna's new movie Battleship, the female reporter asked: "You're so good at connecting with people that I think that we actually feel we know you. Things are clearly going brilliantly in your career. I just wondered if you are as happy in your private life, and will we see a certain Mr Ashton Kutcher perhaps making a trip over here?"
Clearly annoyed, the We Found Love singer replied: "Wow, how disappointing was that question?"
'Having a fling'
When the mediator asked if she wanted to move on to the next question, Rihanna agreed "absolutely" before adding, "I'm happy and I'm single, if that's what you're really asking."
Reports surfaced last week claiming Rihanna started seeing Ashton - who split with wife Demi More last November - eight weeks ago after swapping numbers at a Los Angeles house party.
A source told The Sun newspaper: "The flirting began as soon as Rihanna and Ashton met and swapped numbers. That moved on to texts and arranging to meet. They snuck off to a Santa Monica hotel a few weeks ago.
"They are two single people having a fling, so thought it would be best to meet in secret.
"Rihanna has told friends he's funny and cute. Both of them love a good time and think they're too busy for anything serious just yet."
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