This week was all about keeping it simple (and sexy). And the winners are...

Kristen Bell in Versus at the CBS, The CW and Showtime TCA Party in Beverly Hills. Kristen has a penchant for the prim and proper, so it's refreshing when she takes red-carpet risks like she did here. I only wish she'd rounded out her look with a colorful shoe.

Olivia Wilde in Antonio Berardi at “The Change-Up” premiere in Los Angeles. The 20-something starlet looked red-hot in this structured sheath, which hit just below the knee and featured shoulder padding for more definition.

Dianna Agron in Stella McCartney while visiting the "Late Show with David Letterman." The sheer paneling along the neckline and sides serves as a sexy frame for this otherwise modest LBD.

Leslie Mann in Marchesa at “The Change-Up” premiere in Los Angeles. Beautiful embellishing along the collar, shoulders and waistline proved the bread and butter of this dress. As in the case of Kristen (and, to be honest, Olivia), I only wish she'd chosen a different shoe (maybe something nude or metallic instead of putty).

Sandra Bullock in Lanvin at “The Change-Up” premiere in Los Angeles. While a tad on the casual side, this strapless jumpsuit served to accentuate Sandra's sexy silhouette. She finished off her look with sleek sandals.

Photos (left to right): Steve Granitz/WireImage; Steve Granitz/WireImage; Donna Ward/Getty Images; Jon Kopaloff/FilmMagic; Steve Granitz/WireImage