Britney Spears hasn't lost her focus.
The pop star, 30, recently filmed a commercial for Hasbro's new game Twister Dance, and according to director Ray Kay, "the shoot went really smooth."
"Britney always delivers, and we had a good time on set," Kay, 33, tells Us Weekly. "She brought Jason Trawick and the boys to set, and it was really great to see how her performance was stellar when the boys were watching the monitor. It's like she turned up the performance one notch more."
Spears -- mom to Sean, 6, and Jayden, 5 -- rocked a $20,000 BodyRock Sport by Kelly Dooley sports bra for the ad, which was adorned with 18K gold hardware and embellished with Swarovski crystals.
Kay adds that the engaged singer was "very professional" during the shoot; the last time the two worked together was on Spears' "Till the World Ends" music video, which won Best Pop Video at the MTV Video Music Awards.
"I think the reason Britney's been able to stay on top for such a long while is that she's renewed herself, trying out different kinds of music and expressions throughout the years," Kay tells Us. "She's simply an interesting character."