Disgraced former Rep. Anthony Weiner reported to prison on Monday to serve 21 months in federal prison, after being sentenced in September for sending explicit sexual messages to a 15-year-old girl.

Weiner reported early to a federal medical center in Ayer, Mass., according to the Associated Press.

After he was sentenced, Weiner admitted to being a "very sick man for a very long time."

Upon Weiner’s release, he is supposed to be monitored on the Internet and enroll in a sex-offender treatment program.

Many Democrats still blame Weiner for Hillary Clinton's loss to Donald Trump a year ago. In September 2016, Weiner admitted to sexting a minor, and federal authorities investigated.

In October, the FBI announced it was re-opening its investigation into Clinton's unreleased emails because some of them might have been found on a computer belonging to Weiner and his wife, top Clinton aide Huma Abedin.

The FBI said nothing new was found just days before the election, but Clinton herself says the optics of those announcements is what cost her the White House.