"She called us in the early evening and said she wanted to come shop for Christmas," the store's rep, Kate Diamond, tells PEOPLE. "She looks the best I've seen her in a really long time ... She was really, really nice, saying, 'Thanks, babe,' 'Yeah, babe.' Everything was 'babe.'"
Perhaps she had babies on the brain. After all, Spears, the 26-year-old mother of two, had just recently learned that her 16-year-old sister is 12 weeks pregnant.
"[Spears] bought her mom and her sister Christmas gifts, matching gifts," Diamond said, adding that the pop star also snapped up two By Francine dresses and a Treesje purse for herself.
Given the crowd of paparazzi outside, the store also had security on hand. In an odd twist of fate, IMS Security's Aaron Cohen – the man hired by Kevin Federline's attorney, Mark Vincent Kaplan, to subpoena several of Spears's associates – was this time charged with protecting the singer.
Cohen said that Spears was "so sweet." As for her mood, "She was good, cheery, uppy."
After her shopping spree, Spears ducked into a dressing room and pulled her patented wardrobe switcheroo – changing from jeans into a new short red dress.
The singer and her assistant then drove a few blocks to the nearby Raffles L'Ermitage hotel, where they spent a few minutes at the bar drinking water, soda and coffee before being escorted upstairs.
As the singer was getting in to the elevator, a fan commented on how good she looked in the dress, then asked how her sister is doing. Spears smiled and responded, "Jamie Lynn is good!"