"The are not married," the rep told the magazine.
The Ocean's Eight actress started dating Randall, a photographer based out of Los Angeles, back in 2015.
"They started dating after Bryan photographed [Bullock's son] Louis for his graduation," a source told PEOPLE during the summer of 2015.
The magazine also reported that Randall was with Bullock by the time she decided to adopt her daughter Laila, who was 3 years old at the time.
Bullock's dating history includes former Dallas Cowboys quarterback Troy Aikman, Matthew McConaughey and Ryan Gosling. In 2005, she married motorcycle designer and host of Monster Garage, Jesse James. However in 2010 reports of James' infidelity towards Bullock started popping up, and in April 2010 the Speed actress filed for divorce.
James opened up about his affairs behind Bullock's back in a March 2017 interview with The Daily Mail.
"Yeah, I did cheat on my wife," James said. "Yeah, I stood up and took accountability for it and apologized. And that's end of story. Everything else was just...The easy [potshot] is like, 'Oh, well you cheated on Sandra Bullock.' That's the world's easiest comeback."
"In general, both women and men cheat. It's part of life."
In 2013, James went on to marry professional drag racer Alexis DeJoria. But in June 2016 another cheating scandal broke out, with hairstylist Myla Harris claiming in an interview with InTouch Weekly that she and James had been in sexting conversations over social media.
"I know that's awful because I know he's married," Harris said. "But in the back of my mind, I knew what type of person he was and so I was like, 'Why not?'"
Speculation of Bullock and Randall's potential marriage stretches back to 2016, where a source told E! News the timetable of the duo potentially saying their vows.
"They enjoy the simple and quiet times together," the source said of the pair. "Bryan and Sandra live together, and he helps with Sandra's kids like they are his own."
"Marriage has been discussed, but that's not something that they need to do. They both have been in serious relationships in the past that they have learned from, so they are aware what they want and why they don't," the insider explained.
"They are life partners. They will be spending the holidays together like they always have over the past few years. They are extremely in love. If they do get married, it will be private and under the radar. That's just the kind of couple they are, especially since Sandra's life was so exposed with her past relationship. Bryan respects that."