Jamie Lynn Spears has been named as the trustee of sister Britney's SJB Revocable Trust.

The 29-year-old actress - who is the younger sister of the pop star - has been entrusted to ensure that Britney's personal fortune is transferred into a trust for the singer's kids in the event of her death.

Court documents obtained by 'Entertainment Tonight' reveal that Jamie Lynn was made the trustee of Britney's fortune back in 2018.

At the time, the move was approved by their father, Jamie, and Andrew Wallet, the singer's former co-conservator.

Jamie Lynn is set to receive ''the entire principal of the Trust'', in the event of her sister dying, and she'll be responsible for making sure the money is used to support Britney's children - Sean, 14, and Jayden, 13.

The documents explain: ''The entire principal of the Trust ... shall be promptly distributed by the Trustee to the trustee or co-trustees of the BJS Kids & Family Trust, to be held, administered and distributed in accordance with its terms.''

Last week, meanwhile, Britney was told that her conservatorship will continue until at least 2021.

The 38-year-old pop star requested that her father be permanently removed from the role, but a judge extended the terms of her conservatorship until February next year.

The 'Toxic' hitmaker's dad was appointed to the role when she was placed under the conservatorship back in 2008. However, he temporarily stepped down in 2019 citing health issues, when he was replaced by Jodi Montgomery.

In Britney's filing, she insisted she was ''strongly opposed'' to having her dad return as sole conservator and would ''strongly prefer'' for Jodi to stay in the position.

The singer and her attorney stated they would prefer a ''qualified corporate fiduciary'' to take charge of her affairs.