The 'Bound 2' rapper sang the track for the 65-year-old Caitlyn, who was known as Bruce Jenner before undergoing a gender transition, at her Father's Day celebration on Sunday, reported Female First.
"Out of nowhere, Kanye asked Caitlyn and the others who were there to have a seat because he wanted to say something. "He said, 'This is for you, Caitlyn,' and he just started belting out the most wonderful rendition of Stevie Wonder's 'Isn't She Lovely'," a source said.
"The whole point was for Kanye to convey to Caitlyn that she's lovely and that everyone in that room, including himself, loves her. Caitlyn's mouth dropped and she was in tears. She thought it was beautiful and epic," the source said.