Transformers star Megan Fox and husband Brian Austin Green have announced they are expecting their second child together.

The Hollywood couple, who welcomed their son Noah just 10 months ago, are said to be "very happy" about the impending addition to their family.

A representative for 27-year-old Fox told the New York Post: "I can confirm Megan is expecting her second child with her husband Brian. They are both very happy."

The proud parents tied the knot in a private ceremony in Hawaii in June, 2010 after several years of dating.

They originally got engaged in 2006, but called it off in 2009, only to reunite in 2010 and walk down the aisle.

Green, 40, already has a 10-year-old son Kassius with ex-girlfriend Vanessa Marcil.

Fox has previously voiced her desire to have more children and give Noah a sibling.

"All I wanted to do my whole, whole life was have a baby and, now, I've finally done it," she said in an interview with Marie Claire.

"I just want to give Noah as much of myself as I can. And I want to have more kids. That is where my heart is."

Fox is currently filming Teenage Mutant Ninja Turtles, her first movie since giving birth to Noah.

She plays reporter April O'Neil in the film scheduled for release in June 2014.