Scarlett Johansson, Sean Penn reportedly attend Reese Witherspoon's wedding together

(CBS) Are they or aren't they?

While they continue to keep the public guessing about their relationship status, actors Scarlett Johansson and Sean Penn seemed very much an item when they showed up together to Reese Witherspoon's wedding to agent Jim Toth on Saturday, according to reports.

Pictures: Scarlett Johansson
Pictures: Sean Penn
Reese Witherspoon marries agent Jim Toth

Their arrival reportedly made a bold statement within the A-list guest list, which included actors Renee Zellweger, Tobey Maquire, Robert Downey Jr. and Alyssa Milano.

"Scarlett is Jim's client, but no one, including the bride, knew she would have turned up with Sean Penn," a friend of Johansson's tells Popeater. "Turning up at a wedding with your boyfriend is definitely a huge statement, especially that wedding. What it's doing is announcing to the whole of Hollywood that they are serious."

Rumors about Johansson, 26, and Penn, 50, being an item circulated when the two took a short getaway to Mexico in the beginning of March, about three months after the actress split with husband Ryan Reynolds.

The two were recently spotted getting cozy over dinner last week at the Chateau Marmont Hotel, in Hollywood, Calif., according to People magazine.