Jennifer Garner in NYC on September 27, 2012. Credit: Nicholas Hunt/

Red hot mother of three!

Jennifer Garner looked super sexy at Thursday's NYC premiere of Butter in a red strapless Gucci dress.

The 40-year-old wife of Ben Affleck -- and mom to daughters Violet, 6, Seraphina, 3, and son Samuel, 7 months -- flaunted her slim, toned bod at AMC Lincoln Square Theater.

Garner plays a very type-A mom in the new film, but the actress insists she's nothing like that in real life. 

"I am not like her in any way, shape or form!" she told reporters.

"It was just fun. What was so great about playing this role was getting not to be myself," she added. "I'm sick of myself! I went totally the other way and I had a blast.

Joining costars Olivia Wilde, Alicia Silverstone, the busy mom hit the Cinema Society after-party for Butter hosted by DKNY, Forevermark and with an Appleton Estate Reserve sponsored bar at The Double Seven.

During a recent interview with Ellen DeGeneres, Garner said she's happy with having three children -- but husband Affleck, 40, would like more!

"I am not pregnant right now," Garner said on The Ellen DeGeneres Show. "I plan to be done. But my husband is kind of a wonder sperm kind of guy."

"You never don't know," she added. "You just have a look at him!"