Jeff Kravitz, FilmMagic
The source says that when Franklin was asked to participate, she responded with some variation of, "How could I say no?"
The Rev. Jesse Jackson is also due to appear, NJ.com reports, though he's not scheduled to speak.
"I come to show support for the family," Jackson said.
Whitney's body arrived in New Jersey on Monday night, some 48 hours after she died in Beverly Hills, Calif. Initial reports suggested the R&B great would be laid to rest at the 18,000-seat Prudential Center, but her family later announced plans for an invitation-only private affair.