Michael Andretti, 50, who was the 1991 IndyCar series champion, has three other children from his previous marriages: Marco, 26, who drives for him at Andretti Autosport in the IndyCar series; daughter, Marissa, 22, and son, Lucca, 14, according to usatoday.com.
Cousin John Andretti was quick to offer congratulations, tweeting, "just like our dads." His father, Aldo, and Mario Andretti are twins.
Michael Andretti had a star turn on Donald Trump's "The Celebrity Apprentice" last year in Season 5 but was ceremoniously "fired" on a fourth episode.
He and his third wife Jodi were married in October 2006.