Rep. Rush Holt (D-N.J.) (Photo by Asia Society)

Rep. Rush Holt (D-N.J.) announced Tuesday that he will not seek reelection this year.

"There is no hidden motive for my decision," Holt said. "As friends who have worked with me know, I have never thought that the primary purpose of my work was reelection and I have never intended to make service in the House my entire career. For a variety of reasons, personal and professional, all of them positive and optimistic, the end of this year seems to me to be the right time to step aside and ask the voters to select the next representative."

Holt, who is perhaps best-known in Congress for competing against the Jeopardy! robot, Watson, also ran for Senate in a special election last year, losing the primary to now-Sen. Cory Booker (D-N.J.).

The news was first shared with the New York Times.

Holt is the son of former senator Rush D. Holt (D-W.Va.). He worked as a nuclear physicist and starred on Jeopardy! before joining Congress in 1999.

Democrats are very likely to hold on to the younger Holt's Trenton-based district. It went 67-33 for President Obama in 2012.

Holt is the 20th House member and ninth Democrat to announce he won't seek reelection this year.

Updated at 1:19 p.m.