Shay Mitchell was ''completely blindsided'' by her miscarriage.

The 'Pretty Little Liars' star - who is expecting a baby with her boyfriend Matte Babel - was devastated when she miscarried 14 weeks into her pregnancy last time around and so decided to keep this pregnancy a secret for longer.

Speaking in episode one of her YouTube series, she said: ''I chose to hold on until I announced because of the first time. It didn't go as I had hoped for, and it was extremely difficult. The first time that I was pregnant last year, Matt and I hadn't been planning, it happened and we were really excited about it. I was like 14 weeks, at that point, I had no idea the percentage of miscarriages. When it happened I was just, completely blindsided by it. And it's weird because, I haven't looked at them, obviously. But, it's not like I forgot about that happening, so of course I'm like super happy, but I still feel for that one that I lost.''

Shay announced last month that she is expecting her first child.

Announcing her news on Instagram, she wrote: ''Does this mean I'm allowed to drive in the car pool lane at all times now? (sic)''

And Shay revealed it had been ''hard'' to keep her pregnancy a secret.

She said: ''When you're in the public eye, there are some things you want to just keep a secret until you feel ready. This, for me, has been the hardest. It's going to be really fun and awesome when I'm not trying to hide it anymore. I didn't want to come out on social media so early on. I'm going to be so happy when this comes out. I can be pregnant, like not suck my stomach in.''