Katherine Heigl has opened up about not instantly bonding with her adopted daughter Naleigh.

Although the Hollywood actress has a great relationship with the four-year-old now, Katherine told German newspaper Bild am Sonntag that it wasn't initially easy.

The former Grey's Anatomy star adopted the 10-month-old little girl form Korea back in 2009 with husband Josh Kelley.

"People are always talking about the strong bond between mother and daughter, this magical connection but we didn't have that," the 33-year-old shared.

Katherine revealed that the first few weeks when she got Naleigh home were "the hardest in my life."

"I fought incredibly hard for my daughter to accept me as mother. Her rejection almost broke my heart."

The 27 Dresses star said that she initially focused on her work as a way to cope but that made the "already difficult process of getting closer taken even longer. I immediately cut back on work."

Katherine also revealed that Naleigh bonded with Josh which made her feel like she was a "bad mother" but she soon realised that the "lack of trust had nothing to do with me."

The now happy family are planning a trip to South Korea to show Naleigh "the country that she come from."