It's definitely not an act. Check out what she was about to do to poor Daisy. Nick should have asked for that dog back. TMZ reports [1]:

Jessica Simpson headed through LAX security Monday and appears to have almost sent her dog, Daisy, through the X-ray conveyor belt.

The move turned out to be a near-miss, as Daisy ended up staying clear of the X-ray machine.

After the security snafu, Jessica and Daisy boarded a plane and headed to New York.

At least she got rid of that hideous red wig she was wearing the other day.

Source [2]