Meanwhile, the Countdown star announced in May that she was expecting a baby.
She posted a picture on Instagram cradling a baby bump on the set of the Channel 4 game show, with the letters on the board spelling out “R TINY MATE”.
She wrote: “Pash and I have a conundrum for you… you have till December to work it out!
Maths whizz Riley, 33, and Russian dancer Kovalev, 39, have been together since 2014 after they were partnered in the 2013 series of Strictly Come Dancing.
Riley started dating Kovalev after splitting from her husband and fellow Oxford University student Jamie Gilbert in 2013.
Earlier this year Kovalev announced he was leaving Strictly after eight years on the show.