Beyoncé has given birth to twins in Los Angeles, several celebrity news websites reported on Saturday, citing unidentified sources.
The superstar's father also posted a message on social media.
The award-winning singer, 35, and rapper and music producer Jay Z, already have a five-year-old daughter, Blue Ivy.
E! News, citing multiple unidentified sources, reported the birth and that Jay Z and Blue Ivy were seen at a Los Angeles area hospital on Thursday.
Us Weekly, also citing multiple unidentified sources, reported that the couple welcomed twins earlier this week.
"Bey and Jay are thrilled and have started sharing the news with their family and closest friends," one unidentified source told People.
Mathew Knowles, Beyoncé's father, posted a "Happy Birthday" message to the twins on Instagram Sunday with the caption: "They're here!"
Reuters could not verify the reports. A representative for Beyoncé did not respond immediately to a request for comment. CNN reported the births Sunday, citing "a source close to the couple."
Reports did not provide additional details, such as the date and time the twins were born or the sex of the infants.
The Lemonade singer, one of the most powerful women in the music business, announced the pregnancy on her Instagram account in February along with an image of her posed in lingerie and caressing a noticeable baby bump.
The announcement got more than 8 million "likes" in the first 24 hours to become the "most-liked" Instagram post ever.
Beyoncé performed live at the Grammy awards in Los Angeles two weeks later, proudly displaying her swelling belly in a motherhood-themed show. She has since posted numerous pictures of her bare baby bump on her social media accounts.
The singer's mother, Tina Knowles, posted a video of a baby shower attended by celebrity pals for her daughter in May.
The birth of Blue Ivy caused a paparazzi storm in 2012, with New York's Lenox Hill hospital shutting down part of its maternity wing to accommodate music's royal couple.
News of the pregnancy came less than a year after the release of Beyoncé's 2016 album Lemonade, in which she appeared to address long-standing rumours of trouble in her eight-year marriage.
The lyrics of several songs spoke about being cheated on, and regretting being married. But Beyoncé made clear in the final tracks of the album and in music videos featuring Jay-Z that she had decided to stay in the relationship.
The couple have never addressed the rumours publicly.