KJ Apa split his head open while shooting his new movie.

The 23-year-old actor needed ''metal stitches'' in his scalp after shooting a stunt for romantic thriller 'Songbird' went wrong.

KJ shared photos on his Instagram account, one of which showed him topless on the steps of a trailer while a medic stitched up his wound, and in another, he held up his blood-spattered shirt.

He captioned the images: ''Stunts..''

KJ also took to his Instagram Story to share a gruesome close-up of the injury and explained what had happened.

He said: ''I split my head open yesterday.

''I don't know if you guys can see that, but I have two stitches in there. Metal stitches.''

The on-set accident came just a week after the 'Riverdale' star was left in pain when he got a piece of metal stuck in his eye.

The actor shared a two-minute video on Instagram of the agonising removal process.

He captioned the video: ''a shard of metal got stuck in my eyeball (sic)''

In the clip, he told the camera: ''I'm not trying to do that. I'm not trying to do this right now. I have to work tomorrow! It's actually like punctured my eye!''

Once the piece was out, his pal Jason Schneidman, who was assisting, said: ''You got the piece out, bro. That's the piece that was f****** in your eye.''

KJ later reassured fans that he planned to seek medical advice but was feeling ''fine''.

He said: ''Quick update here, guys. The eye is good. I'm seeing a doctor tomorrow. My appointment's at eight o'clock.

''I just want to say thanks for all the support. I appreciate it a lot.

''My eye's fine. But there could be some more metal shards in there, rusting away in my eyeball.''