Credit: NATIONAL PHOTO GROUP

Jamie Lynn Spears, 19, provided a rare glimpse of 2-year-old daughter Maddie last week during a Los Angeles outing with mom Lynne and the baby's father (and former fiance), Casey Aldridge, 20, with whom she split earlier this year.

Are the exes on-again?

They are "not together," a source tells UsMagazine.com.

The two made headlines in 2007 when Britney's younger sis -- formerly the star of Nickelodeon's Zoey 101 -- announced that she was pregnant at age 16.