American singer Christina Aguilera reunites with her ex-husband Jordan Bratman for a family day with their son Max on August 11, 2013. Credit: AKM-GSI

Xtina's body just keeps getting better! Christina Aguilera once again showed off her skinnier frame during a casual family outing in Venice Beach, Calif. on Sunday Aug. 11 -- and her ex-husband was on hand to notice the singer's latest transformation. Not yet donning a bikini, the Grammy winner still offered a glimpse of her shrinking frame in a white tank top, tight ripped jeans and flip-flops and she and music producer Jordan Bratman had a fun day out with Max, their adorable 5-year-old son.

More grown up than ever, Max looked like a perfect mashup of his parents with dirty blonde hair and pouty lips. Photos from the day out show no tension between Aguilera and Bratman, 36, who finalized their divorce in 2011 after six years of marriage. Aguilera has moved with boyfriend Matthew Rutler, who she's been dating for nearly three years.

As for her talked-about new figure, the 5-foot-2 "Feel This Moment" singer "has been on a mission to lose weight," a source recently told Us Weekly. Already shedding 20 pounds, the star is "making better choices" with her diet and has "adopted a new lifestyle" in terms of daily fitness routines, the source adds -- logging in regular yoga and strength training, yoga, and hiking.

Raved her Voice cohort Carson Daly to Us recently: "She's in crazy good shape!"