Matt Damon is speaking out on behalf of close friend and co-star Ben Affleck. Rumors have been swirling abut the "Batman" actor since June 30 when he and estranged wife Jennifer Garner announced their plans to divorce. More than a month after their initial announcement, Damon, 44, is addressing Affleck's, 42, post-split demeanor.

According to People magazine, the pair appeared at the red carpet premiere of HBO's "Project Greenlight" on Monday. While Affleck chose to forego questioning from reporters, onlookers said he appeared to be in good spirits. He is said to have signed autographs for eager fans, laughing as one handed him a "Daredevil" poster to sign. Damon happily stopped to talk with the media at which time he was asked about his friend. He claimed Affleck was doing fine, adding that he had "a big smile on his face."

While Affleck and Garner, 43, have stated that they planned to move forward with "love and friendship," they've been forced to face some nasty rumors surrounding their marriage. On July 29, nearly a month after their initial announcement, it was reported that Affleck and the family's nanny, Christine Ouzounian, were having an affair. Multiple outlets claimed the pair had gotten close while spending time together playing with his and Garner's three children. They were said to be extremely flirtatious. The alleged relationship escalated from there leading to alleged meet-ups at hotels and Affleck's rental property. 

Reps and sources close to Affleck have been adamant about any and all rumors of an extramarital affair being untrue. Still, stories continue to surface revealing new details about the alleged affair. On Aug. 5, it was reported that Ouzounian, 28, may have been tipping off the paparazzi in an attempt to make their business relationship appear to be something more. She has been accused of having called photographers to alert them to her meetings with Affleck among other things. Friends of the nanny say she was fired shortly after being hired and kept strangely quiet on the matter, which they said was unlike her. 

Neither Affleck nor Garner have directly spoken out about the rumors surrounding their marriage. Throughout the entire divorce process the soon-to-be exes have remained focused on their three children, spending time together as a family. Affleck was recently spotted jetting to Atlanta, Georgia, to be with daughters Violent and Seraphina and son Samuel, who are living there while Garner finishes filming for "Miracles from Heaven."