"LT is 6 months old today!!" Taylor wrote alongside a photo of little Leo sandwiched between herself and his mama.
In another pic that shows Leo gnawing on Taylor's hand, the 26-year-old pop star marveled at how time flies: "Pretty wild that 6 months ago, LT wasn't even born yet and now he chews on my fingers," she wrote.
Jaime, 36 -- a longtime member of Taylor's squad -- has said she just knew that Taylor was the right woman for the job when it came time to choose her second son's godmother.
"It wasn't because it was this person and the name. It was really because of her morals and her values, the way that she treats people and how hard-working she is," Jaime explained to People. "That's the kind of person I want to be the guide and the spiritual protector of my child."
Jaime also took to Instagram to share a few snapshots with Taylor and her little boy on Jan. 16.
"This one goes in the baby book. Godmother love #LeoThames and@taylorswift 🐼," Jaime wrote alongside a snapshot of the three of them standing in front of a wall of bamboo.
In yet another photo -- this one of Taylor and Leo gazing into each other's eyes -- Jaime gushed, "What love looks like... LT and TS ♥️."
Taylor hosted a star-studded baby shower for Jaime before Leo's birth in July. Leo is the model-turned-actress' second son with husband Kyle Newman, a director. (Big brother James Knight Newman was born in 2013.)
So what kind of godmother is Taylor, really? "I mean how is Taylor at everything in her life? She's amazing," Jaime told a group of reporters including Wonderwall.com at the Art of Elysium's ninth annual Heaven Gala in Los Angeles on Jan. 9.