The couple are already parents to 21-month-old daughter Milan.
Over the weekend, the former boxing champ was spotted rubbing his wife's belly over dinner at Ago inside Las Vegas's Hard Rock Hotel. She also showed off her baby bump recently in New York at the premiere of ESPN's One Night in Vegas, a documentary about the death of rapper Tupac Shakur and her husband's 1996 fight against Bruce Seldon.
"They are very happy and everyone is doing great," Tyson's rep tells PEOPLE.
The announcement of Tyson's wife's pregnancy comes more than a year after the former boxing champion's 4-year-old daughter, Exodus, died when her neck accidentally got wrapped in a cord of an exercise machine.
Two weeks after the tragedy, Tyson and Spicer wed in Las Vegas in a private ceremony.