Britney Spears at LAX on June 18.
has arrived at the Mississippi hospital where her sister Jamie Lynn
is expected to give birth to her first child today.
On Wednesday, Britney – along with her father Jamie and brother Bryan – arrived in her hometown
of Kentwood, La., to be with Jamie Lynn. Mom Lynne has also been with Jamie Lynn, helping prepare for the baby's arrival.
The Spears family spent a relaxing evening together in Liberty, Miss., where Jamie Lynn recently bought a home, the night before. "They have had nine months to deal with this," says a Spears family friend. "Last night was very low-key. There was no last-minute panicking. No one was worried."