The former “Fuller House” actress has been told that federal prosecutors in Massachusetts will use 21-year-old Isabella Rose and 20-year-old Olivia Jade Giannulli “as star witnesses in hopes of securing a conviction,” a source told Us Weekly.

Loughlin, 55, asked if there was anything that could be done to keep the girls from testifying — but was told the only solution would be to change her plea to guilty, the source told the gossip magazine.

Both she and her 56-year-old fashion designer husband have pleaded not guilty to allegations they forked over a $500,000 bribe to get their daughters into the University of Southern California as bogus rowing recruits.