The first-time parents shared the good news on their respective Instagram accounts.
In her post, Dianne, who is 17 weeks pregnant, said she could not be more grateful for this gift.
In the caption of her post, the actress wrote: "Easter is all about celebration of New Life.
"Today, as we celebrate the Resurrection of our Lord Jesus Christ, we are also celebrating this gift of NEW LIFE inside me! [smile emoji]
"We are immensely happy to announce that Rj and I are expecting! I'm 17 weeks pregnant! [smile emoji]."
In January this year, she told PEP.ph her desire to "build a family already."
Dianne continued, "We couldn't be more thankful to our God for blessing us with this baby on the way, and we thought it's just fitting to share this with you all on Easter day.
"Even if we are in this dire situation, we can hope for a brighter future ahead because Jesus has risen, and this is the bedrock of our faith.
"Please pray together with us on this journey. God bless and protect us all! Happy Easter!
"Thank you, LORD! So happy! #HoneymoonBaby #AnsweredPrayer #DreamComeTrue"
For his part, Rodjun said in his post: "Answered prayer! [heart eyes emoji] Thank you, Lord. The best ka talaga. We love you! #babycomingsoon #happyeaster."
The couple's feed overflowed with congratulatory messages from their celebrity friends.
Heart Evangelista wrote: "Woooooooow [heart] congrats !!!"
Bela Padilla said, "Congratulations!!!! [heart]"
Kim Domingo was also happy for the couple: "Congrats!!! [heart eyes emoji]," she wrote.
Dianne and Rodjun were married on December 21, 2019, at the Manila Cathedral in Intramuros, Manila.