The blissed-out couple (and Wanderlust co-stars) got engaged in New York City on Aug. 10, Theroux's 41st birthday. Two months later, Aniston debuted her huge new bling: a radiant-cut center diamond (approximately 8 carats) worth an estimated $500,000. "Jen is over the moon about her second chance at a happy marriage," a source told Us of the actress, who divorced Brad Pitt in 2005. "Justin is giving her a solid vow to love."