Berkshire-born Nicholas, 24, who first met Jennifer in 2011 on the set of X-Men: First Class, has spoken about how they have coped with their increasing fame over the years.
"The privacy thing obviously changes but the rest pretty much stays the same," he told V Man magazine. "It’s like that thing whereby you don’t believe your own hype. Enjoy the good times, but don’t get swept away with it."
Nicholas, who sat proudly next to Jennifer at this year's Oscars, added that the Kentucky-born star knows how to deal with her ever-growing fame and will remain down-to-earth.
"I think that’s something she’s capable of doing, and that’s what makes her special," he said of the 23-year-old. "But yeah, it is very odd, and I am just kind of a bystander in many ways. It is well-deserved for her. I haven’t really seen any change in her."
"It’s fun because in this business you are away from one another for long periods of time," added Nicholas, who has recently finished filming X-Men: Days of Future Past with Jennifer. "So when you’re on set together it’s a brilliant thing, because you actually get to spend time together.
"Especially with this film, I got to spend time with her... It doesn’t really affect the acting though."
Jennifer and Nicholas at the Golden Globes
As this year's award season began, Nicolas praised his girlfriend's numerous nominations, saying that she "deserves it all."
Jennifer, who won the Oscar for Best Actress in a Leading Role in 2013, had plenty of reason to celebrate as she scooped a Golden Globe and a BAFTA for her role in American Hustle.