Are Cameron Diaz and Benji Madden going to get married soon?

The 42-year-old actress has sparked speculation that she is already engaged to the Good Charlotte guitarist after she was seen wearing a shiny diamond ring set on her engagement finger (the fourth finger of her left hand) during two occasions Wednesday, Oct. 8.

The "Sex Tape" actress was first spotted wearing the ring set at the Hollywood Costume Luncheon Wednesday. She was then seen wearing the same jewelry again while sporting a completely different outfit later that night on a romantic dinner date with her 35-year-old rocker boyfriend at Madeo in Beverly Hills, Daily Mail reported.

The jewelry set in question is comprised of a twisty, figure-eight design ring with diamonds and another diamond band. See it here.

Diaz and Madden were first linked in May, according to Hollywood Take.

The following month, the couple was spotted holding hands, confirming rumors that they were indeed an item, according to Hello Magazine.

And over the fourth of July holiday, Diaz introduced Madden to her family in Tampa.

"They flew into Orlando and then drove to Tampa where they met up for a reunion," a source tells E! News. "They also spent a few days at the beach on Anna Maria Island, where Cameron's family has a house. It was a great vacation and they had a blast spending time with Cameron's nieces and nephews."

And though their relationship is still pretty new, the two are said to have already talked about their future together including the possibility of marriage.

"They are openly acknowledging to friends that they see a long future together, and yes marriage may be a part of that plan," a source told E! News in July. "It's being discussed, whether seriously, who knows."

"Benji has pretty much moved into her house in Beverly Hills, and they've talked marriage," a friend of Diaz revealed to Page Six. "None of us would be surprised if she called us and said: 'Guess what? I'm Mrs. Madden!'"