The close friend of Prince William, who has recently dived with crocs for a new TV series, tweeted: “I would like to take Sean Penn and place him in the jaws of one of those crocodiles.”
He added: “We are all entitled to our own political opinion on the Falklands but it’s up to the islanders not actors to decide their future.”
He also challenged Penn to a public debate on the Falklands.
Penn, Madonna’s left-leaning ex-husband and UN ambassador at large for Haiti, claimed that continuing British hold on the Falklands was “colonialist, ludicrous and archaic”.
The following day he accused the UK of “insensitivity” for sending Prince William to the South Atlantic territory.
Penn, 51, said: “My oh my, aren’t people sensitive to the world colonialism, particularly those who implement colonialism.
‘It’s unthinkable that the United Kingdom can make a conscious decision to deploy a prince within the military to the Malvinas [the islands’ Spanish name], knowing the great emotional sensitivity both of mothers and fathers in the United Kingdom and in Argentina who lost sons and daughters in a war of islands with a population of so few.
“There are many places to deploy the prince. It’s not necessary, when the deployment of a prince is generally accompanied by warships, to send them into the seas of such shared blood.”
Falklands hero and former Welsh Guardsman Simon Weston also branded Penn an “idiot” and a “fool” over his comments.
The 50-year-old father of three, who was injured in an Argentine bomb attack that killed 48 people in 1982, said: “People give far too much credence to actors. Sean Penn is living, breathing proof that just because you are famous doesn’t mean you know what you are talking about.
“Penn is an idiot. It’s bad for people to think you’re a fool. You don’t need to open your mouth to prove it. By opening his mouth on this, Sean Penn proves he is a fool.”
Tory MP Patrick Mercer also called Penn “moronic”.
Britain has refused to negotiate while Falklanders want to remain part of the British realm, and is increasing its military defences in the run up to the 30th anniversary of Argentina’s failed attempt to gain control of the islands.