The married couple broke the news by posting identical images on Twitter.
One showed Glover standing on a boat while flashing her baby bump and the other was of Backshall with two goslings.
Deadly host Backshall tweeted: “On the boat with my three favourite people; seems this summer we’ll have some little ones of our own... @Helenglovergb.”
Olympic rower Glover, 31, tweeted: “Soooo...The biggest adventure of our lives.. 2 little (chicks) of our own arriving this summer!!! @SteveBackshall.”
Fans were quick to congratulate the pair on the “brilliant news”.
Soooo...The biggest adventure of our lives.. 2 little ]]>🐥🐥