The 71-year-old singer - who was the late star's cousin - explained she saw the 'I Will Always Love You' hitmaker as her own daughter, and her tragic death last month still hasn't ''sunk in''.
Dionne said: ''Whitney basically was the little girl I never had. She is and always will be very, very much alive here.
''It hasn't really sunk in yet. I have not really had an opportunity to mourn or completely break down, which I will do. I know that. I think the comfort comes in knowing she's in good hands now.''
The 'That's What Friends Are For' singer explained she spoke to Whitney on the morning of her death and the troubled star seemed ''happy'' and had ''everything in the world to live for'' as she prepared to attend a pre-Grammy function held by producer Clive Davis.
Dionne added in an interview with 'Good Morning America': ''She was up and ready and happy. I spoke to her that morning.
''She said, 'You're here, aren't you? You're coming to the party, aren't you?' I said, 'Yeah, I'm going to be there' and she said, 'Thank you, I want you to be here. You've got to be here for me'.
''She had everything in the world to live for. She had everything in the world to live for. She had a new film, that was an absolute dream to make and do, and completed that, thank God. She was getting ready to go back into the studio to record, she was getting her vocals together.''