Fetty Wap Jets in for Baby Birth ... Masika's In labor!

Ex "Love & Hip Hop: Hollywood" star Masika Kalysha is ready to pop -- she went into labor on Tuesday, and baby daddy Fetty Wap ... is rushing to be there for the birth.

Masika's rep tells TMZ she went into labor around 12:30 PM, and she instantly notified Fetty. We're told he booked the first flight out of New Jersey and has now landed in L.A. The rep sent us this shot of mommy-to-be in her hospital room.

We're told Fetty wants to be at the hospital when the kid arrives. He and Masika have come a long way. Remember, Fetty originally denied even being the father.

Based on his tweets ... sounds like Fetty is pretty happy about the pending arrival.