The 38-year-old actress uploaded a photograph of herself walking down the streets of New York.
In the caption of the image, Tyler expressed her shock and said that she couldn’t wait to see her baby.
“Oh my goodness look at that bump. So pointy and giant! I can’t wait to meet the beautiful little human living in there,” Tyler wrote, reports aceshowbiz.com.
The Armageddon star flaunted her baby bump in a short sleeve black crochet dress which featured a tight inner. She also donned wayfarer sunglasses and carried a sling bag which she designed for British high-end brand Belstaff.
Tyler announced that she is expecting her second child with Gardner in January, but the pair have yet to reveal the sex of their baby.
She also has a 10-year-old son ,Milo, from her previous marriage to musician Royston Langdon.
On the other side, Gardner has son Grey with ex-wife Davinia Taylor.
Tyler was last seen in the movie Space Station 76 and Jamie Marks Is Dead. She will next be seen in Wildling in which she stars opposite Finding Nemo actor Ellen Cooper.