Aaron, who for decades held the record for most home runs ever hit, pinch-hit for Nunn's campaign on Tuesday, writing a fundraising letter to her supporters.
Aaron goes on to say he's been "truly impressed" by Nunn's "commitment to service, to helping Georgians empower themselves, and to making our state a better place."
Aaron is one of Georgia's most famous athletes, and one of the best-known and most popular baseball players in history. His support could help Nunn, who's been running as a centrist, both reach across party lines and rev up African-American excitement about her campaign.
Nunn will face businessman David Perdue (R), who won his primary earlier this week.