Serena Williams and her fiancé Alexis Ohanian welcomed their first child, a baby girl, yesterday, and we couldn't be more thrilled for the couple. We're not the only ones freaking out, either—a ton of Williams' famous friends had sweet messages for the new mom and baby.

The 35-year-old tennis player unintentionally announced her pregnancy on Snapchat back in April, and we've been eagerly awaiting the arrival of "Baby O" ever since. It's all too fitting that Williams' first child arrived in the middle of the U.S. Open on Friday!

There was no shortage of well-wishers once the good news reached the Internet. Among the first to send sweet thoughts to Williams was Beyoncé, who posted a pic that read "Congratulations, Serena!"

Singer Kelly Rowland posted a beautiful maternity pic of Williams, writing, "Congratulations to my incredible friend on the birth of her little one!"

Singer Ciara, another longtime friend of the tennis star, took to Twitter to say she's "so happy" for the new parents.

TV host Wendy Williams came through with a great pun on Twitter, writing that "You Reddit here first." We see you, Wendy.

Other well-wishers included tennis great Billie Jean King and Williams' coach, Patrick Mouratoglou.

There's no shortage of love for this lucky little baby!