Kiernan Shipka had a "mental breakdown" over turning 25

Speaking on 'The Drew Barrymore Show', she said: "I was freaking out before. I would quite literally just be going about my day and then sort of descend into some sort of mental breakdown, which happens. I'd be freaking out about a random thing and then I'd go, 'And I'm turning 25 too!' Like it would just happen, it would just come over me.

"The day of felt great. It was just the lead up that made me freak out a little bit. But I'm happy to be 25."

The former 'Mad Men' star previously explained that others have described her as being "wise beyond [her] years" but started to feel "younger" with each passing year, and thinks that this could have been down to her "unconventional" life experience so far.

She told TheTalks: "People always told me that I was wise beyond my years. I never really believed them at the time but then I started to feel younger as I got older, if that makes any sense. I started to feel very professional at a young age, but then dealing with other life experiences was totally new to me. It was definitely unconventional."

Just recently, Kiernan recalled a heavy night with friends which resulted in a mysterious injury.

She told PEOPLE magazine: "I drank so much with my friends one night, and I woke up the next day and I had - I tell you - a massive hump on my nose.

"My nose literally went out a little and then back in."

Even now, the 'Twisters' star doesn't actually know how the injury actually happened, but "it lasted a couple of weeks".

She said: "I don't know if I fell. Unclear how it happened. It lasted a couple of weeks. It was a big Christmas mishap."