Rachel revealed the exciting news in a statement today, saying that she and Alex are "super excited" about having a new addition to their family.
The couple, who married in a glitzy wedding at Claridge's in London in 2009, already have a two-year-old daughter together called Amelie.
Rachel, 35, and 36-year-old Alex said: "We're so happy to find out that we are pregnant again and can't wait to meet our new little member of the family early next year.
"Needless to say, we're all super excited, especially Amelie who is looking forward to meeting her younger brother or sister."
Along with their announcement, the couple also shared an adorable photograph which shows a pair of shoes for each of them, Amelie and their unborn child.
Underneath each pair is the years they were born written in chalk. Too cute!
See who else is expecting in our gallery of pregnant stars below:
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