Jimmie Johnson and wife expecting second child

Jimmie Johnson and his wife Chandra are expecting their second child.

"We are so happy to share news that we're having another baby in September," Johnson announced on twitter on Tuesday. "Genevieve is so excited to be a big sister!"

Johnson's daughter, Genevieve, will be three in July.

Johnson has won two of the first six races of the Sprint Cup season and goes into this weekend's{}race at Texas Motor Speedway as the series points leader.