The pop star is set to perform later in the service.
The couple showed up to the 4,000-seat Greater Grace Temple in Detroit, Michigan, and were almost immediately greeted by former President Bill Clinton and his wife, former Secretary of State, Hillary Clinton.
The 25-year-old pop star was seen talking at length with Hillary prior to the start of the ceremony as Franklin's family made their way to their seats. Grande, Davidson and the Clintons also posed for photos while mingling.
Grande was dressed in a black dress, with her trademark ponytail as high as ever. As for Davidson, the 24-year-old Saturday Night Live star looked dashing in a black suit, which is a far cry from his usual super casual attire.
In addition to the 18 performances, the six and a half hour service will also have former President Clinton, Tyler Perry, Cicely Tyson and Smokey Robinson speaking.
You can view the full funeral line-up HERE.
The ceremony is set to conclude at 3:00 p.m. ET, after a performance by Jennifer Holliday and the Aretha Franklin Celebration Choir. However, it may go a little longer as it got off to a late start.
The Queen of Soul died on Aug. 16 after a battle with pancreatic cancer. She was 76.