Natalie Cole Honored by Stevie Wonder, Lionel Richie at Memorial Service: 'I Feel So Blessed to Call You My Friend,' Smokey Robinson Says

Friends and family of Natalie Cole gathered to honor the late singer Monday morning.

Mourners, including Gladys Knight, Johnny Mathis, Jesse Jackson, Angela Bassett and Linda Thompson remembered Cole at a nearly three-hour long private memorial at the West Los Angeles Church of God in Christ, her rep confirms to PEOPLE.

Stevie Wonder and Kurt Carr sang, while speakers Lionel Richie, Chaka Khan (who was expected to perform but apologized for being too hoarse to sing), Smokey Robinson and David Foster paid tribute to the singer at the closed-casket service.

“I feel so blessed to have called you my friend, and my buddy, and many times my confidante,” Robinson said, according to CBS LA. “You are so real and down to Earth. Now I have to say you’re so real and up to heaven.”

Cole’s son Robbie and sisters Timolin and Casey also spoke at the funeral, which was presided over by the Rev. Melvin V. Wade, Cole’s rep tells PEOPLE.

“What a woman,” Robbie said after carrying his mother’s Bible to the podium, according to the Associated Press. “She taught me how to love. She had my back every time when I needed it. The greatest gift she ever gave me was Jesus. I cannot wait until that day that I see you again.”

Cole was 65 when she died of heart failure on Dec. 31. The Grammy-winning R&B singer (and daughter of jazz legend Nat King Cole) is survived by her son and sisters, who released the following statement upon her passing:

“Natalie fought a fierce, courageous battle, dying how she lived … with dignity, strength and honor. Our beloved mother and sister will be greatly missed and remain UNFORGETTABLE in our hearts forever.”

Cole’s heart failure was brought on by idiopathic pulmonary arterial hypertension (IPAH), a rare lung disease. But IPAH was just one of many conditions she struggled with over the years: In addition to a lifelong battle with addiction, she underwent a kidney transplant in 2009 after complications resulting from her 2008 hepatitis C diagnosis.

“My sister was a warrior in the best sense of the word,” Casey Cole Hooker said at the service. “In the end her body simply began to give out and it shut down. She was long accepting of what was coming and trying to make us OK.”

“You shouldn’t have regrets,” Cole, who won nine Grammys in her nearly 40-year career, told PEOPLE in 2008. “I’d say instead that I’ve learned a lot of lessons. Yes, I could have handled some things better. But they’ve also made me who I am today. I like myself so much more than I did even five years ago. I can’t think of anything I wish I hadn’t done, even with this hepatitis.”

Cole was later buried privately Monday afternoon at Forest Lawn Memorial Park in Glendale, California.

• With reporting by CHRISTINE PELISEK