The duo apparently text each other frequently and the singer is thought to be still enamoured by the British photographer.
"Britney and Adnan are constantly on the phone or text messaging each other," said an insider. "Britney gets excited when he calls or texts because he lavishes her with compliments.
"Adnan searches the internet for photos of her and then calls and comments on her outfits and her hair, and she loves it."
The source added: "She also wears the promise ring he gave her when they were dating."
Spears split from Ghalib in March after allegedly discovering raunchy text messages from other women on his iPhone.