UPDATE: Beyonce and Jay Z's Twins Remain Hospitalized

June 18, 2017

Anthony Gruppuso - USA TODAY Sports

UPDATED (Tuesday, 6/20):
We're now hearing more details about why the "Carter twins" remain hospitalized more than a week after their birth. 

TMZ says that the twins were born prematurely, and they are "under the lights to normalize. Of course, it is pretty common for twins to arrive a little early. "Under the lights" usually just means that the babies are jaundice. The condition is related to elevated bilirubin levels. So the lights are used to help counteract that.

It's not clear when the twins will be released. But this is a common condition, and we're hearing that everyone is expected to be OK.

Beyoncé and Jay Z are parents once again! The power couple welcomed their new bundles of joy into the world a few days ago, PEOPLE is reporting. 

Not much is known about the birth or the twins at this point. Beyoncé's Dad, Matthew Knowles, acknowledged the news in a Father's Day post online:

TMZ is actually reporting that the bundles of joy arrived last weekend. Doctors have not released the twins from the hospital, however, because of a "minor health issue." TMZ is reporting that Beyoncé and the twins are expected to be just fine. 

There is speculation that the couple welcomed a boy and a girl. That is, however, only based on what balloons have been spotted being delivered to the hospital, according to reports

The twins join big sister Blue Ivy who turned 5 years old in January.