The Die Hard star welcomed his first child with model Heming last year (12) and it seems 20-month-old daughter Mabel will soon become a big sister.
The British beauty, 35, first sparked rumours she is expecting again at the weekend (15Dec13), when photos obtained by Wenn showed Heming sporting what appeared to be a baby bump as she enjoyed a day out at a California farmers' market with Willis, 58, and young Mabel.
Multiple sources have since claimed the pregnancy rumours are true, although a representative for Willis has declined to comment.
The couple wed in 2009.
Willis is also father to grown-up daughters Rumer, Scout and Tallulah, with his ex-wife Demi Moore.