The two have been dating for more than a year now and Shayk flaunted her baby bump while walking the runway at the 2016 Victoria's Secret Fashion Show last month, reported E! online.
"Irina and Bradley are so excited to be parents. They have already picked a few names they like. They know the sex but are still deciding between some names," a source said.
The two are thinking about expanding their family even more.
"Bradley and Irina love each other so much and this is not gonna be the only kid-there will be a few more after this one. Both families are very happy," the source added.