Britney Spears' cell phone use is reportedly "heavily monitored".

The singer has her internet usage and phone calls checked in order to protect her, according to RadarOnline. The star has apparently had all her contact with the outside world vetted for a period of four years.

"Britney's cell phone and internet use is restricted and heavily monitored, and this is done for her protection," a source revealed to Radar Online. "Britney's father, Jamie, and her fiancé, Jason, want to make sure that her former manager, Sam Lutfi, isn't able to contact her."

Sam is suing Britney and her parents for defamation and breach of contact. Britney's conservators are responsible for ensuring the singer doesn't find out anything negative written about her by Sam prior to the trial. They therefore decided to block her access to certain websites and restrict the numbers that can come through as calls on her phone.

"Britney and Jason essentially share a cell phone, and it's routinely checked to see who has been calling..." the source continued. 'Her family doesn't want Britney reading negative stories that would upset her. Again, this is all done with love and for her well-being."