Lawyers for Sam Lutfi declined to say whether he would be the first witness at Monday's trial in Los Angeles.
But one thing certain was that Spears will not testify. She remains under a court-ordered conservatorship and a judge told her not to participate.
Her father, Jamie, who is her conservator, has been in court with his wife, Lynne, whose book on her daughter's darkest days led to the defamation suit by Lutfi.
He was portrayed by lawyers for the family as a destructive force in Britney's life. His lawyers maintain he was just trying to help Britney and manage her career.
Lutfi is seeking millions of dollars from Spears and her family.