Blake Lively is certainly one of Hollywood's most attractive young starlets. In this image, Blake has a classic False Smile though. It is commonly known as a False-Surprised Smile or Dropped Jaw Smile (B. & A. Pease). With a true, felt smile - the forehead is relaxed - but Ms. Lively's forehead is contracted across its entire width. With true surprise, the expression is very brief - nearly always less than a second or two. We cannot tell the duration of Blake's expression, of course, because this is a photo. It is valuable to keep this in mind though - for if you see a surprised expression, and it lasts longer than 1 or 2 seconds, at least a portion of it (or perhaps the entire emotion) is being faked or exaggerated. This is a red flag - dig deeper.
Another sure sign that this is not true surprise, is that Ms. Lively's eyelids are not opened wide. With true surprise, the eyelids are opened wide enough to see the whites of the eyes (sclera) ABOVE the iris (colored part of the eye).
Blake Lively - beautiful but not believable (here in this photo). Blake is not surprised, nor is this a sincere smile, but a common expression that looks (to most people) like both, but is neither. Things are not always as they seem. Don't get fooled by professional actors or those around you whose motives may be questionable.
Secret # 702: Mouth of Fear, Trying to Smile and Forehead of Pain
Analysis # 2: Body Language of Blake Lively and Penn Badgley Strongly Suggests an Impending Break-up in Near Future
Nonverbal Communication Secret # 2091: Sincere Smiling (a la' Blake Lively) and Laughing Reduces Anxiety and Heart Rate, Boosts Immune System and Relieves Pain
Nonverbal Communication Analysis # 2203: A Body Language Metric of Intimacy and Affection - How Do YOU cuddle?