Beyonce's twins were born June 13 in Los Angeles

July 19 (UPI) -- Celebrity couple Beyoncé and Jay Z welcomed their twins June 13 in Los Angeles, according to new details that emerged this week.

Birth certificates show the pair's daughter and son, Rumi and Sir Carter, were delivered by Dr. Paul Crane at Ronald Reagan UCLA Medical Center, according to TMZ.

Crane is the same doctor who delivered Kourtney and Kim Kardashian's five children, as well as Rob Kardashian and Blac Chyna's daughter, Dream. Rumi was born first, at 5:13 a.m., with Sir delivered shortly after.

The birth certificates clarify that neither Rumi nor Sir have a middle name. Beyoncé had confirmed her twins' names last week while sharing a first photo of the pair on social media.

"Sir Carter and Rumi 1 month today," she captioned a photo of herself with her daughter and son.

Beyoncé and Jay Z, who married in 2008, are also parents to 5-year-old daughter Blue Ivy. Sources told People this week the 35-year-old singer and 47-year-old rapper have been keeping a low profile and focusing on their family.

"They are very excited about adding babies to the family," an insider said. "Jay was great during Beyoncé's pregnancy and continues to be great. He loves being a dad and Beyoncé seems very happy."