The six-time Olympic champion cyclist has been sharing his joy about the happy news.
"It's a very exciting period of my life and for me and Sarra, hopefully a wonderful experience," he said.
Chris, 38, retired from cycling last year and he says the timing of the pregnancy couldn't have been better.
However, he admits that there are some aspects of parenting that he finds daunting.
"Everybody I speak to when I ask about them and their experiences about becoming a parent, they mention lack of sleep, which I'm not great with so that'll be a big challenge," Chris told Sky Sports News.
"I think maybe I'm just blindly optimistic that it's going to be great fun and dead easy. I'm sure it won't be, I'm sure there'll be lots of tough things but I'm just very excited. It all seems to have happened at the right time."
Chris added that he doesn't know how people cope with having children while they're competing - which is something he may want to discuss with fellow Olympic champs Jessica Ennis-Hill and Zara Phillips.
Jessica, who is due to give birth to her first baby next month, has said she plans to return to competition and hopes to compete at the Rio 2016 Games.
While Zara, who gave birth to her first daughter, Mia, in January has become something of a dab hand at balancing a baby and sporting events, as she has already returned to competitive horse riding and also hopes to compete at the Rio 2016 Games.
competitng in sporting events
More:Pregnancy Week By Week
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