Diplo is having a baby with his ex-girlfriend Kathryn Lockhart - their second child together and a sibling for four-year-old son Lockett.
It's thought Kathryn was "newly pregnant" when Diplo began dating Katy Perry in April of this year.
Speaking to the New York Daily News newspaper's Confidenti@l column, a source said: "She's due in the next couple of weeks. Her friends recently had a baby shower for her. She and Wes aren't together, but he's actively involved in (Lockett's) life."
The news comes weeks after Katy said she was feeling "in control" of her new relationship, wanting to keep the romance "undercover".
A source revealed: "She's keeping this one undercover because she's learned her lesson. She's in control, but he likes that.
"He knows she's in charge and respects her. She keeps tabs on him ... but she trusts him and that's the most important thing to her."
Diplo has already been introduced to Katy's family as the relationship gets more serious.
"Her family likes him a lot. You can see how comfortable she feels with him already because the whole crew hangs with him already and they approve. It's important that everyone gets along with him because makes her crazy life easier."
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