Sandra Bullock is not dating Jonathon Komack Martin.
The 47-year-old actress was rumoured to have hooked up with Jonathon - the business partner of her best friend Ryan Reynolds - at a private party in Los Angeles last month.
A source told Now Magazine: ''They met years ago, but nothing ever happened - until now.
''Sandra's been spending time with him, going to parties or just hanging out at her house. She says they both have the same silly sense of humour.''
But the 'Blind Side' actress - who divorced 'Monster Garage' host Jesse James in 2010 amid reports that he had been unfaithful - insists Jonathon is just a good friend, and that she only has eyes for her adopted son Louis, two.
She told US website Gossip Cop: ''For over a decade now, I have been so lucky to have Jonathon and Ryan as my friends, and I agree with the reports that they are both very handsome and a great catch!
''But the only man who has stolen my heart is my son. And for now I wouldn't have it any other way!''