With the Illinois primary less than three weeks away, Rep. Timothy V. Johnson (R-Ill.) has announced he is backing the Senate bid of fellow Rep. Mark Kirk.

Kirk faces five little-known GOP challengers in the Feb. 2 primary, the most prominent of whom is real estate developer Patrick Hughes.

Kirk, however, is expected to win the GOP nomination.

Until Tuesday, Johnson was one of two GOP Members in the delegation holding out on endorsing Kirk; Rep. Don Manzullo (R-Ill.) has said that has a policy not to pick sides in primaries.

Illinois GOP Reps. John Shimkus, Aaron Schock, Peter Roskam and Judy Biggert have already announced they are backing the five-term Congressman.

“Mark Kirk shares my commitment to job creation, economic growth and care for our nation’s veterans,” Johnson said in a statement. “Mark will be a Senator we can all be proud of.”

CQ Politics currently rates this general election contest as a Tossup.