By Meghan Blalock
Updated Apr 18, 2013 @ 10:30 am
Alexis Bledel
Credit: Brian To/; Gregg DeGuire/WireImage

Mad Men co-stars Alexis Bledel and Vincent Kartheiser revealed that they were dating last summer—around the time Bledel guest-starred as Kartheiser’s mistress on Mad Men—and have been together ever since. Last month, the pair announced their engagement, and Bledel finally debuted the sparkler she said "yes" to—an octagonal diamond set in a band with pavé stones decorating the sides—at the premiere of her made-for-TV movie Remember Sunday in Los Angeles last night. "I'm a very lucky man," Kartheiser had shyly told reporters last October. And she's a lucky lady, too! So, now that you see it close up, what do you think? Leave your unfiltered thoughts in the comments.

See more celebrity engagement rings in the gallery.