One Tree Hill fans – brace yourselves…

one tree hill jackson brundage birthday 19

Credit: Getty

Because sweet little spiky-haired James Lucas Scott is no longer so.

Jamie Scott actor Jackson Brundage has left fans shook after celebrating his 19th birthday.

Yes – NINETEEN!

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Haven’t posted in months sooooooo Hi!❤️

A post shared by Jackson Brundage (@jacksonb4real) on

The former child star rose to fame in the teen (turned adult) drama series when he joined the cast in the fifth series.

Jackson hit screens back in 2008 when he was a mere seven years old, playing longtime characters’ Nathan Scott’s and Haley James Scott’s (AKA our beloved Naley) four-year-old son.

He won over loyal viewers as Jamie, with his adorable blue eyes, witty comments, oversized basketball jerseys and his uncanny resemblance to certain Scott brothers, and over the years (even across a second time jump) fans watched as Jackson grew up to play a talented, popular and caring pre-teen.

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The gang❤️ #oth

A post shared by Jackson Brundage (@jacksonb4real) on

But fans couldn’t believe it when it was revealed earlier today that the actor, who quickly became a staple part of the iconic cast that included Hollywood stars Chad Michael Murray, Sophia Bush and Paul Johansson, had turned 19!

Fan account OTHdiary took to Twitter with a birthday celebration for the star, writing ‘Happy 19th birthday to the one and only @TheRealJacksonB, also known as Jamie Scott!’.

And fans refused to believe the actor’s birthday, disbelieving of how fast the last decade has flown by.

He’s 19?! Omg where did the time go? 😭,’ wrote one fan, while another commented, ‘No, this can’t be true. I’m not that old, I don’t accept this! 💔’.

‘19.. I just .. no .. it’s baby James Lucas Scott 😭😭😭,’ added another, while one exclaimed, ‘Holy Mother of Neptune he’s 19!?🥺🥺🥺🥺’.

MORE: Whatever Happened To… Chad Michael Murray?

Another wrote, ‘it blows my mind that we are the same age but yet i can only see him as this little boy!’.

Other fans added, ‘19????? I feel old’, ‘how is he 19 😫’, ‘That’s crazy!! 😲’, ‘I can’t believe your 19 😱💓’ and ‘19?!!! Wow I’m old 😭😭’.

Happy birthday Jackson! 💔