The 26-year-old model announced her pregnancy in a lengthy article posted on Monday (13Feb17) on Derek's sports news website The Players' Tribune.

After writing about her love for her 42-year-old husband, whom she married last year (16), Hannah announced her big news to fans.

"Big moments also have a funny way of making you look ahead," she wrote. "Now, pregnant with our first child, Derek and I are looking to the future."

In the gushing piece, which includes a photo of Derek holding a bouquet of pink balloons, confirming the couple are expecting a girl, the Sports Illustrated Swimsuit Issue cover girl also revealed the former athlete had already decided upon a name for the child whom Hannah refers to as "her".

She added, "He already has a name in mind - he's set on it. (We'll see.) He'll say when he calls me during the day: "So, how are you and so-and-so doing?" (and I'll reply) "That's not the name yet, sweetie." Whatever her name is, I know she'll run circles around him."

Indicating the couple were planning to have more children she added, "We want our kids' lives to be as 'normal' as possible. They're going to be born into such an extraordinary situation. They're going to have to be some strong little people."

Derek spent almost two decades in a successful New York Yankees baseball team, winning five World Series championships before his 2014 retirement.

However Hannah does not want her and Derek's offspring to be defined by their famous father, explaining, "We don't want them to be defined by their dad's name - for them, we want him to just be "Dad." That will be the piece of him they'll have that the rest of the world doesn't. It will be special, and it will be theirs."