Hollywood's worst kept secret is FINALLY out in the open.
The pair were snapped holding hands during a romantic stroll along California's Malibu beach over the US Labour Day Holiday weekend.
Rumours about the couple began as far back as August 2013 but the pair reportedly have always kept the romance under wraps, apparently due to a clause in Katie's 2012 divorce from Tom Cruise, which forbid her from going public with a boyfriend for five years.
That's like being in lock-down between the end of filming for The Bachelor Australia, until the finale airs - BUT FOR FIVE YEARS. Sorry Matty J and your Chosen One, you've got nothing on Jamie and Katie.
But with the restrictions running out around July-August, the lovers are know happy for the world to know about their romance.
Let's look back at their not-so-secret-secret relationship!
Jamie and Katie are spotted dancing, arm in arm at the 4th Annual Apollo in the Hamptons benefit.
And this immediately sparks romance rumours between the pair.
WATCH: the moment Katie and Jamie hit it off! Post continues after the video...
In an interview with Entertainment Tonight Jamie reveals that relationship rumours are "one hundred percent not true."
Giving a decoy quote to throw the world off the scent, he says: "In fact, it's quite hilarious because we simply danced at a charity event along with a lot of other people."
Almost a year-and-a-half since rumours first began to swirl, the pair are pictured holding hands in a recording studio.
"Jamie is someone she can trust and have fun with," a mutual pal tells Us Weekly.
"She's getting everything from Jamie that she didn't get with Tom."
Katie is a special guest at Jamie's star-studded 48th birthday bash in New York.
An insider reveals to US Weekly Katie has been going to extreme measures to meet up with her man and at one point even "put on a wig and hat to meet him" for a hotel rendezvous in LA.
Katie plays coy about the romance and refuses to talk about her love life during an interview.
"That's not something I want to answer," she tells More magazine.
The couple reportedly jet off on a romantic getaway to Cabo San Lucas, Mexico to celebrate Katie's birthday.
"Katie and Jamie took a private jet to Cabo on Friday morning from Van Nuys Airport [in Los Angeles]," an insider tells Us Weekly.
"It was a quick trip in honor of Katie's birthday. It was only them and two pilots on the plane."
Before Jamie flies to Budapest to start filming his new flick, Robin Hood, the duo are spotted dining out together in New York City.
In the snap, the actress grins as she chats to her companion. Keeping a low profile, Katie was dressed down in a black jacket, a sleek ponytail and a pair of glasses.
Jamie, 49, is pictured side on, so is a little harder to distinguish, however his trademark white hat can be seen.
Once again the pair are busted.
This time in none other than the romantic city of love, Paris!
Jamie is already in France, having wrapped filming on Robin Hood so, Katie flies into Paris to meet him.
"They stayed inside their hotel... and didn't leave," a source tells E! News.
"They were very discreet and made sure to always enter and exit the hotel and the car separately. Jamie had a big smile on his face as they returned to their hotel and snuck in through a private entrance."
Oh la la!
Jamie is caught spending the day with Katie and her daughter Suri Cruise before she started back to school.
According to the Daily Mail onlookers saw Jamie arriving at Katie's home with treats for the girls.
And it's official!
Jamie and Katie are all smiles on Malibu beach, laughing and splashing in the waves together during a romantic stroll!