Joseph Kennedy III announcing bid for Congress

Joseph Kennedy III is formally jumping into the race for the Massachusetts congressional seat now held by retiring U.S. Rep. Barney Frank

The Democrat's campaign says he'll make the official announcement Thursday. 

Kennedy says he believes the United States was founded on the idea every person deserves to be treated fairly "but that's not happening in America anymore." 

Kennedy recently moved from Cambridge to Brookline, part of the state's newly redrawn 4th Congressional District. 

Kennedy is the son of former U.S. Rep. Joseph Kennedy II and a grandson of the late Robert F. Kennedy. The family has deep ties to the Boston suburb. 

Kennedy announced last month he was forming an exploratory committee to look at a possible run for the seat. 

At least two other Democrats and two Republicans are considering runs.