A little girl! We're both thrilled and can not wait to meet her, ' the future dad captioned the photo.
His retirement news came after years of concussions causing health issues; he also has plans to work as a broadcaster for FOX Sports and be involved in other off-the-track ventures.
Earnhardt Jr., who is 43, and Amy Wednesday on New Year's Eve last winter.
Earnhardt, 43, is retiring from full-time NASCAR competition at the end of the current season, which has five races remaining.
Earnhardt has never won a Cup Series championship, but has been NASCAR's Most Popular Driver 14 years running.
Dale Earnhardt Jr. and his wife, Amy, have shared the happy news that they're expecting their first child - a little girl!
Look out, NASCAR! Another Earnhardt is on the way. And it would be weird not being a race-car driver if I have a daughter or son.
There was no due date on Earnhardt's Instagram post, but on his Twitter, Earnhardt explained that he and Amy learned they were expecting on September 1.
Turns out Earnhardt picked the right time to retire, after all.