The 32-year-old actress joined co-stars including Adam Scott, Amy Poehler and Jane Lynch at the Landmark Theatre in Los Angeles where she showed off her new look and was dressed to impress in a cropped black top and black skirt, reported Contactmusic.
On her way to the premiere, Alba posted a picture of her newly short tresses on Facebook and wrote, "Love my new haircut."
'A.C.O.D.' (Adult Children of Divorce) tells the story of Scott's character Carter, who is still dealing with his parents' divorce 20 years later and discovers he was an unknowing participant in a study about children of divorce.
'A.C.O.D.' will be released in the US on October 4.