Tiffani Thiessen is expecting a baby boy.

The former 'Saved by the Bell' actress - who recently announced she is pregnant again - is set to welcome a son with husband Brady Smith into the world later this year.

The 40-year-old star, who already has four-year-old daughter Harper, confirmed they recently made the happy discovering during a routine medical check-up.

The brunette beauty unveiled the news in the latest issue of PEOPLE magazine by cutting into a white gender reveal cake with a blue interior.

She added: ''We could not be more excited about extending our family. Harper is beyond thrilled to have a playmate!''

Tiffani - who married 'The Jensen Project' actor Brady in 2005 - previously admitted Harper was desperate to have a sibling.

Speaking about her and Brady's decision to try for another baby, Tiffani said: ''With Harper, it happened right away so I'm hoping it'll be easy this time around.

''Every day she begs me to have a baby.

''Every morning she wakes up and days, 'Is there a baby in your belly?' She thinks it grows overnight while we're sleeping. Then she looks at me and says, 'You're not growing a baby, Mommy!' ''