Apparently it happened on Saturday. Even though she's not confirmed via Twitter (apart from posting the obligatory "totes amaze" over the weekend), everyone else has for her.
Edith Bowman: "MASSIVE congrats to @MrsLRCooper and family on the arrival of their little girl. So much happiness and love going their way. Xxx."
Jonathan Agnew (AKA the BBC's cricket correspondent): "Many congrats to @MrsLRCooper and Sam on birth of their first child. Lovely news to wake up to."
Amanda Holden: "Massive congrats to lily and Sam! Such good news. Xxxx."
Charlie Condou (AKA Marcus off Corrie): "She has indeed, a little girl."
While Myleene Klass kept is simple: "congrats."
After a miscarriage, and then losing another child at 6 months, Lily's determination will do doubt give hope to the legions of others tirelessly attempting to become parents.
