Update, 4.45pm: Sebastian has been found safe and well.
Thank you to everyone who shared our appeal, it is very much appreciated
Have you seen Sebastian? The 21-year-old has missing from the Lincoln area since the early hours of today (15 January).
He is described as 5ft 10ins tall, medium build, with short blond hair, and blue eyes.
Sebastian may be wearing a dark coat with a fluffy rim on the hood, a hat, and white trainers.
If you have seen him, or have information that could help our search, please call 101.