A teenager jumped in front of a subway in Brooklyn Wednesday morning — severing his leg, cops said.

The 19-year-old leaped off the northbound platform of the G train as the subway entered the Myrtle-Willoughby Avenues station around 10:45 a.m., according to police.

His leg was severed and he was taken to Bellevue Hospital in stable condition, cops said.

G train service resumed with some delays around 12:45 p.m., an MTA rep said.

Additional reporting by David Meyer