Although he's already leading in polls and gaining endorsements, Joseph Kennedy III has yet to officially enter the race for Medfield's Fourth Congressional District.

But that will all change Thursday morning.

In a press release issued Wednesday evening, Kennedy's campaign said he will offficially announce his candidacy Thursday, Feb. 16. A video announcement will be posted on www.joekennedy2012.com in the morning. 

Following his announcement, Kennedy is set to make five stops in the district, starting in Newton. He is scheduled to appear at the Newton Centre MBTA stop at 7:45 a.m. 

After Newton, Kennedy will travel to Milford, Attleboro, Taunton and Fall River. 

“I believe this country was founded on a simple idea: that every person deserves to be treated fairly, by each other and by their government, but that’s not happening in America anymore,” Kennedy said in the press release. “I've spoken to people from across the 4th Congressional District - from Newton to Fall River - who believe that Washington no longer works for them. I will work hard to earn every vote and if elected bring that fight for fairness to the US Congress.”

Kennedy announced last month he was forming an exploratory committee to look at the seat, which will be open following the retirement of longtime Congressman Barney Frank. He moved to Greenough Street in Brookline and is registered to vote in the district as of Feb. 9.

Along with Kennedy, former Frank challenger and Democrat Rachel Brown, Attleboro Democrat Paul Heroux, Sharon Democrat Marty Farren and Brookline Democrat Jules Levine have announced plans to run for the seat. Brookline Library Trustee and Patch columnist Michael Burstein has said he will form an exploratory committee to look at the seat.

Newton Democrat Herb Robinson made a decision to run early on, after leaving his campaign to run for U.S. Senate. 

Former Fourth District contender Sean Bielat and Brookline School Committee member Elizabeth Childs have also said they will run on the Republican ticket.