A spokesperson for the couple confirmed the news, adding the pair were 'thrilled' to be expecting another baby to join their older children, Violet, five and Seraphina, two.
The news comes after the couple were forced to deny Jennifer was pregnant back in May, after the rumour mill went into overdrive over her apparently 'rounded' tummy. At the time, her spokesperson released a statement saying: 'The speculation is false, she is not pregnant.'
Jennifer and Ben have been married for six years, after tying the knot in June 2005.
See who else is expecting this year with our gallery of celebrity baby bumps...