Boris Johnson's father Stanley says he's applying for a French passport for 'symbolic and sentimental' reasons.
The 80-year-old author and former Conservative MEP made headlines when he confirmed his application for French citizenship just before the UK formally left the EU.
Despite his son being considered one of the foremost advocates for the leave campaign, the older Mr Johnson voted remain.
He told The Pat Kenny Show that he wants to 'build bridges' with the Europe - and joked he could try for an Irish passport as well since his middle name is Patrick.
In terms of the French passport, he said: “It’s sentimental: my mother was born in France. Her mother was French, her grandmother was French… she took it very, very seriously.
“Then I’d say there’s a symbolic aspect to this as well. I voted remain: I actually helped set up in the UK an organisation called Environmentalists for Europe.
“I think the crucial thing now that the Brexit deal is well and truly done…it is going to be tremendously important to build these bridges with Europe.
"I do not know whether this exercise will come to fruition - but yes I've done it, and there's no point trying to keep quiet about it."
He stressed he will be keeping his British passport, and that he's not just trying to skip the travel queues in airports and the like - although said there may be some benefits in that respect.
He said the process for getting French citizenship is 'slightly more complicated' than anticipated - including having to send French authorities a 'very specific set of documents' such as his grandmothers' birth cert.
Despite his support for staying in the EU, Mr Johnson said he's a democrat and totally accepts the outcome of the 2016 referendum.
He said: “I don’t think I’m alone in this: I say it wasn’t just the June 2016 vote which got us out of the EU… that vote was confirmed on several occasions, including most recently the 2019 election.
“You could say when history comes to be written, people may say the relationship of the UK with the EU was an uncomfortable one.
"I can see… maybe the UK didn’t fit so well in the federalising context.”
One of the consequences of Brexit has been concerns around many of the shelves in Northern Ireland supermarkets being empty due to shipping delays and other complications from the new regime.
Mr Johnson, however, said he believes that's something that will be sorted out before long.