The couple is pictured in an Instagram photo Wednesday holding a picture from a baby scan.
A spokesman for Daley confirmed that "Tom and Dustin are thrilled to share that they are expecting their first child in 2018."
Daley, 23, and Black, 43, announced their engagement in 2015 with an announcement in the Times of London, and wed last year.
Daley has competed at three Olympic Games and won gold in the 10-meter platform event at the 2017 world diving championships.
Black is an American screenwriter and director who won an Academy Award in 2008 for his screenplay for "Milk," a biopic of gay-rights campaigner Harvey Milk.
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