The 35-year-old singer is expecting her first child with Orlando - who already has nine-year-old son Flynn with his ex-wife Miranda Kerr - and sources have said the couple are thrilled to be starting a family of their own.
An insider claimed: "Katy has wanted a baby for a long time. She and Orlando both have. They have so much fun with Flynn and being parents, they couldn't wait to add to the family."
Katy has a "special bond" with Flynn and "can't wait" to see him be a big brother to her child, as the source also claims the singer has a "great relationship" with Flynn's mother Miranda.
They added: "Katy has a great relationship with Miranda and they have always been supportive of one another. Miranda has always appreciated Katy's love and care for Flynn.
"From the very beginning, Katy has had a special bond with Flynn, and she can't wait to see him be a big brother."
The insider also believes the 'Never Worn White' hitmaker will be a "great" mother, because she already has experience with Flynn and her friends' children.
The source said: "Between Flynn, being an aunt and being around all of her friends' babies, she has had a lot of experience, and now it's her turn. She will be a great mom and a natural."
Katy is said to be "so excited" for the next year of her life, which will also see her tie the knot with 43-year-old Orlando.
Another source told E! News: "Her and Orlando have always wanted a baby. It was one of the first conversations they had since being engaged and they both were always on the same page.
"Katy is so excited and feels it's finally the right time in her life. It didn't matter to her if the baby came before the marriage or vice versa because she knew she had found her soulmate."
