Serena Williams gushes over 'so special, so fun' daughters

Serena Williams expressed joy over being a mother of two!

As the legendary sports gushed over her daughters one-year-old Adira and six-year-old Olympia, whom she shares with her husband, Alexis Ohanian.

Williams took to her official Instagram account to upload some throwback snaps of her maternity shoot, featuring her and Olivia before they welcomed Adira.

With Adira turning a year old, the proud mom of two could be seen smiling alongside her elder daughter in a bed of flowers, in the tribute post.

"Olympia is always there for me," Williams kicked off in her caption, adding, "Before having a second child, I always wondered, 'how could I love anything as much as I love @olympiaohanian?'"

She continued, "Then Adira came along … she is so special, so fun, so funny, so loving, so sweet and so strong!!! You see, God makes your heart get bigger. Because my love for Olympia has not dimmed. My heart simply now is doubled the size and I have a greater capacity to love more!"