Houston's life and legacy were celebrated by the likes of Perry, Stevie Wonder and Kevin Costner at the New Hope Baptist Church in Newark, just one week after she was found dead in her LA hotel room.
The Good Deeds director urged Houston's family and friends to not simply mourn her death, but also remember the many happy memories of her life.
Perry told those in attendance at the Newark church: "There are two constants that I know about Whitney Houston. There was a grace that carried her from heaven... a grace that brought her up through singing. The other thing I know for sure - Whitney Houston loved the Lord."
The filmmaker spoke about the memorial service on CBS This Morning on Monday (February 12) and admitted that he was intimidated to be chosen by Houston's family as the first speaker.
"The family asked me to do it. Our entire relationship has been private. Nobody even knew that I knew [Houston] and that I've been in her life for the last four years," Perry told Gayle King. "They asked, so I [spoke]. I would have much rather… not even have to have been at a funeral for her."
Perry and King also reflected on the final moments of the funeral, where Houston's mother Cissy and daughter Bobbi Kristina looked on as the singer's casket was carried out of the New Hope Baptist Church.
"It was unbelievable. That whole moment summed it up for me. No matter how much we loved [Whitney], no matter how much we cared about her, the truth of the matter is [Houston] was [Cissy's] daughter and [Bobbi Kristina's] mother. That was the most difficult part."
Houston was laid to rest in a private ceremony at the Fairview Cemetery in Westfield, New Jersey on Sunday (February 19).
More Whitney Houston Coverage:
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> Bobby Brown: "I love you, Whitney"
Watch Whitney Houston's 'Exhale' music video below: