The 24-year-old reality TV star and cosmetics entrepreneur posted a black and white picture showing a hand holding the child's tiny hand on Instagram, where she has 309 million followers, on Sunday.

Some reports said the hand was that of her sister, four-year-old Stormi.

The baby, the picture caption said, arrived on 2 February, the day after Stormi's birthday.

Jenner, known to millions from reality show Keeping Up With The Kardashians, did not reveal the newborn's gender.

But alongside the picture was an emoji of a blue heart, which may indicate it's a boy.

Houston-born rapper Scott, 30, posted a series of love heart emojis.

Jenner's famous siblings also sent their congratulations, with Kourtney Kardashian commenting "Mommy of two life" and Kim Kardashian posting an emoji showing a baby with a halo.

Khloe Kardashian posted four blue love hearts.

Kris Jenner, who now has 11 grandchildren, wrote "Angel Pie".

When did Jenner and Scott get together?

Jenner and Scott, a chart-topping rapper whose songs include Highest In The Room and Sicko Mode, first started dating in 2017, with Stormi arriving the following year.

They reportedly split in 2019 but were said to have rekindled their romance shortly after.

Jenner chose to keep her first pregnancy private and did not go public with the news until Stormi was born in February 2018.

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This time, the couple announced news that their second child was on the way in a 90-second video shared to Instagram in September.

Jenner held a baby shower in January.

It comes after 10 people died as fans surged toward the stage during a performance by Scott at the two-day Astroworld music festival in Houston, Texas, in November.

Scott has said he did not know fans were injured until just minutes before a press conference following the show.