Michael Jackson was secretly romancing his children's nanny Grace Rwaramba, his personal photographer has revealed.

The 'King of Pop' who died at the age of 50 after a suspected cardiac arrest, had a long relationship with the Uganda native, claimed Ian Barkley his personal photographer.

"Grace loved Michael and he loved her.. it was an open secret among staff," said Barkley.

According to the photographer, Jackson's children used to call 42-year-old Rwaramba "mom", reported the Mirror online.

Barkley, who travelled the world with the 'Thriller' hitmaker for three years as his personal photographer says that Jackson fell in love with Grace, 42 after she became the nanny of his children in 1999 following his divorce from Debbie Rowe.

She acted like a normal mother to Prince Michael, 12, Paris Katherine, 11 and six-year-old Prince Michael II behind closed doors, claims Barkley.

Jackson’s former head of security, Matt Fiddes had earlier claimed that the King of Pop had a secret lover but he had refused to reveal her name.

Fiddes who has known Jacko since the 1990s, said, "The family were aware that there was someone special in his life who he loved and adored and had his ups and downs with.

For some time she's been present in his life. She wasn't a celebrity figure, absolutely not."