The former Corrie star, 33, announced the good news on Twitter early this morning (Sept 15).
She wrote: "Ryan & I are overjoyed to announce that we are expecting a baby! Feeling very blessed!"
Ryan & I are overjoyed to announce that we are expecting a baby! Feeling very blessed!— Katherine Kelly (@katherine_kelly) September 14, 2013
Katherine and Australian digital analyst manager Ryan, also 33, dated for two years before eloping to Las Vegas on August 20 to get married in an intimate ceremony at the Little Church Of The West.
Last night, just hours before announcing the news, Katherine arrived at the 30th birthday party of former co-star, Corrie's Catherine Tyldesley, in Manchester and showed off just the hint of a bump in a loose black dress.
She left Corrie in 2012 after six years of playing troubled Becky McDonald, and has since appeared in Mr Selfridge and Field Of Blood.
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