Britney Spears Shops for her new niece

The singer went shopping at the True Religion Warehouse with her mom Lynne on Friday—and Jamie Lynn's little girl was first and foremost on her mind.

Britney specifically picked out items for her new niece, Maddie Briann, from the toddler collection. Everything from T-shirts and hoodies to jeans for the little girl, a source tells E! News. She also selected some similar clothes in boys' styles for Sean Preston and Jayden James.

For herself, Spears picked up tank tops, T-shirts and jeans, to name a few. She loved True Religion's new puffy jackets for fall, scooping up a vest and a hooded jacket, both in red. She also liked the headwear—she chose some baseball hats as well as a winter-weight fedora.

"She was very happy," says the source. "She loved trying everything on. She looked great."

According to a source, Britney did not mention Madonna or the video shoot she's been busy with. She was focused on shopping and was very gracious.

"They had a great time—they thanked us when they left," a source tells E! News. "They were very polite and sweet."

After shopping, Britney and mother Lynne headed to ABH, the new rooftop hot spot at the Thompson Beverly Hills Hotel. The mother-daughter duo munched on sushi rolls and sipped soft drinks from Bond St., the restaurant downstairs, along with an assistant and bodyguard.

"Britney was very mellow, normal, grateful and sweet to staff," an onlooker tells us. [source]