Joseph Kennedy III, a Democratic congressman from Massachusetts, is eyeing a primary challenge to Sen. Edward Markey, a report said Friday.

Kennedy, the 38-year-old grandson of Robert F. Kennedy, told a Democratic official this week that he is considering challenging the 73-year-old Markey instead of running for re-election next year, the New York Times reported.

Kennedy and his staff members have not publicly commented on the plan, but an adviser to Markey said he planned to fight any challenge to his seat.

“Ed is not going anywhere,” Paul Tencher, a senior Markey adviser told the Times. “He’s going to run, and he’s going to run no matter who is in this race.”

Last month, Politico reported that someone was poll-testing a matchup between Markey and Kennedy — creating speculation he may challenge him for the seat.

At the time, a spokesperson for Kennedy said he planned to run for re-election, but didn’t deny that he had commissioned the poll.