An Irish Sea first is happening this morning.
Hundreds of men are wading into the wintery waves at a beach in Skerries in Co Dublin to raise funds for male cancer care at the Mater Public Hospital.
The Dickie Dip is "an all-male, bare-all swim" with participants "braving the Irish Sea wearing only a dickie bow at a secret location in Skerries."
According to the Mater Foundation: "To learn where the beach is, and to register for the event, just join our Facebook Group and fill out this sign up form."
Organiser Dermot Higgins says the Dickie Dip is a life-affirming event.
"We've got 200 brave souls who are braving the cold water of the Irish Sea," said Mr Higgins.
"It's not a nice day but we are going to dip into the Irish Sea today to raise funds for prostate cancer care."