Beyonce welcomed a boy and a girl with husband JAY-Z last month.
Rumi and Sir Carter aren't the only twins in Beyonce's family!
The singer's father, Mathew Knowles, revealed on Instagram on Wednesday that multiples are part of the Knowles ancestry.
WATCH: JAY-Z Is All Smiles at the Gym After Twins' Birth and New Album Announcement
"In the research that was done for [my new] book, I was able to learn about my heritage, my family, and going back to my great, great grandmother," Knowles explained. "I was also learning that my grandmother, Hester, actually had brothers that were twins, Sidney Moore and Gitney Moore!"
"You can see that the twins started in our ancestry, and Beyonce should be proud of that," he added.
Beyonce welcomed a boy and a girl with husband JAY-Z in June, and appeared to have revealed the babies' names (Rumi and Sir) in trademark paperwork obtained by ET last week.
The couple has yet to officially confirm the names of their new additions, however, JAY-Z did reference his and Beyonce's newborn twins in a song off his new album, 4:44.
See more in the video below.