Winehouse sat in the front row during Blake Fielder-Civil's appearance on Monday.
The 24-year-old singer smiled at him repeatedly and patted the empty seat next to her. At one point, she mouthed the words, "Come and sit here next to me."
She gave a handwritten note to a court official and asked him to deliver it to Fielder-Civil. No one could see what she had written.
Winehouse told spectators outside the court that her husband looked gorgeous.
