The couple are already parents to their one-year-old son, Christopher Carlton Cumberbatch, who was born in June last year.
A rep for Benedict confirmed the news to Reveal, and told us: "Everyone is absolutely thrilled."
Benedict and Sophie haven't yet publicly addressed the news themselves - they are known for being notoriously private when it comes to their relationship and family life.
Confirmation Sophie is pregnant again comes after the couple recently stepped out at the Hollywood premiere of Benedict's new movie and Marvel release, Doctor Strange.
He and Sophie first met while filming for Burlesque Fairytales in 2009. They announced their engagement in November 2014, revealing the news in an announcement included in The Times newspaper.
It read: "The engagement is announced between Benedict, son of Wanda and Timothy Cumberbatch of London, and Sophie, daughter of Katharine Hunter of Edinburgh and Charles Hunter of London."
Benedict and Sophie went on to tie the knot in a private ceremony on the Isle of Wight last year, on Valentine's Day 2015.
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