Mama’s protecting her little cash cow. Lynn Spears has insisted that soon-to-be son-in-law Casey Aldridge sign a prenuptial contract in order to protect Jamie Lynn’s assets.

“Lynne is keeping an eye on him.”

“The contract is already drawn up and ready to go,” a mole tells In Touch Weekly. “Lynne’s not sure marriage is a good idea, but she’ll go along with that if that’s what Jamie Lynn wants — as long as Casey signs the contract.”