Migos rapper Offset is seeking joint custody of his seven-year-old-son, after admitting paternity in a child support suit.

The hip-hop star, who recently got engaged to fellow rapper Cardi B live on stage, has admitted fathering a child with Justine Watson, according to court documents obtained by website The Blast.

She had filed documents seeking to establish Offset, real name Kiari Kendrell Cephus, was her son, Jordan's dad, and to compel him to pay child support.

In his response, Offset, 25, claimed he had provided for the child since birth, and editors at the gossip website report that he is seeking joint legal and physical custody of Jordan, and wants to change the child's surname to his own.

Watson claims that Offset, who is worth an estimated $9 million , provided some financial assistance, but rarely contributed to medical expenses, nor financed his son's educational needs.

She is demanding retroactive child support and $15,000 in attorney's fees - a payment Offset is disputing.

The rapper, who has acknowledged fathering two other children with different women, proposed to Cardi B on stage at a concert in Philadelphia, Pennsylvania last month (Oct17).

According to The Blast, two days after the pair became engaged, he filed to make the financial information in his paternity case secret.

Offset and Cardi appear to be planning a lavish wedding, as the Bodak Yellow musician told New York magazine "the world is not ready" for their nuptials.