"Annie" star Cameron Diaz, who's reportedly engaged to Good Charlotte guitarist and vocalist Benji Madden, is publicly displaying a large ring on her ring finger.

With an accompanying photograph, Us Weekly said Tuesday that Diaz, 42, dramatically placed the bauble in front of her face while running errands in West Hollywood Monday. The magazine said she also wore what it described as a thick gold band while taping the UK talk show "The Graham Norton Show" on Dec. 16. A friend of Madden told People that the proposal "happened a few nights ago" and that "all of Benji's friends are aware and happy for him."

Diaz and Madden have been dating since May, according to reports.

Representatives for Diaz and for Madden, 35, did not respond to Newsday requests for comment.

Diaz and New York Yankee Alex Rodriguez had an on-again, off-again relationship since at least July 2010 before breaking up for good in September 2011. Her previous boyfriends include actors Matt Dillon and Jared Leto, and singer-actor Justin Timberlake.