The Bridget Jones' Diary star is attempting to become an official citizen of the country after talking about his "horror" over the UK's decision to leave the European Union, according to the Daily Star.
A source told the newspaper: "Colin was horrified by Brexit and is worried about the consequences."
The actor has been married to Italian film producer Livia Giuggiolo for 20 years and is reportedly worried that she could be deported once Britain splits from the EU.
He thought Brexit was a "disaster"
The couple currently live in Chiswick, west London with their two sons Luca, 16, and Matteo, 13.
They also have a holiday home in Umbria, northern Italy.
Colin speaks fluent Italian.
He was openly against Brexit, and said after the referendum: "For me this is a disaster.
"Brexit does not have a single positive aspect. Many colleagues, including Emma Thompson are, like me, enthusiastic Europeans."
Colin has been married to Italian film producer Livia Giuggioli for 20 years
Mirror Online has contacted Colin's representatives for comment.
Meanwhile, Colin could be about to give musicals another go after a Mamma Mia! sequel was confirmed.
Executives at Universal Pictures have given the green light to the eagerly-anticipated follow-up, which has the sub-title: Here We Go Again.
Colin, Meryl Streep, Pierce Brosnan and Amanda Seyfried are all due to reprise their roles, while casting agents are also speaking with supporting talent, such as Christine Baranski.
They have two sons
The soundtrack, which will feature heavily in the film, will comprise of ABBA tracks that weren't featured in the original.
The script will be penned by London-born writer Ol Parker, who's married to Thandie Newton and also created The Best Exotic Marigold Hotel.
Currently, Mamma Mia: Here We Go Again! has been given a theatrical release of July 20, 2018, although it could be slightly delayed if post-production exceeds provisional deadlines.