Photographers snapped the pair getting into a car together, along with actress Joanna Garcia, after the three attended the two-year-anniversary of Bardot, a Los Angeles nightclub.
A source told E! Online: "They definitely came together and sat together. Cameron would lean over and chat with Matthew, but it didn't seem too flirty."
The insider added: "Diaz and Garcia seemed tight and had a great time. Matthew and Cameron had some one-on-one time in the lounge, but nothing seemed too intimate.
"Matthew seemed to be a huge gentleman and genuinely cared for both ladies the entire night."
