The Senior Year singer shared a picture of her daughter dressed in a pink sleeper with mittens and amusing unicorn socks,
The announcement of the birth comes months after Wilson, 42, disclosed that she was dating Ramona Agruma.
Even though she made no mention of co-parenting, the Australian performer thanked those who made it possible.
She said, "This has been years in the making, and I am forever thankful to everyone who has been involved, (you know who you are).
" But I wanted to thank my wonderful surrogate in particular since she carried the baby and gave birth to her with such dignity and care.