Donna's bulletproof confidence is awe-inspiring, making her one of the series' best-loved characters in Suits.
Sarah Rafferty says friendship with Macht is an asset on Suits set.
In the world of Suits, Donna Paulsen is a legend. Smart, strong and fiercely loyal, barely a week goes by when she doesn't save the day. Or more specifically, when she doesn't save Harvey Specter's day.
But in real life, it was Gabriel Macht - who plays Harvey - who saved the day for actress Sarah Rafferty, an old friend from drama school.
"It was Gabriel who gave me the script," she explains. "I had done a pilot and I was waiting for news on whether it was going to get picked up, and it wasn't. The same day I got that news, I saw Gabriel and told him. He said, 'Great, you need to read this script tomorrow ...'
"I put myself on tape because they were doing auditions in New York City and I was in LA at the time. The rest is history."
That was six years ago. Speaking to the Herald from Toronto, where the cast is halfway through shooting season six, Rafferty says she could never have believed how successful the legal drama would become.
"I had been in the business long enough to know and to have experienced the disappointment of 'almost' scenarios," she says.
Though her role in the pilot was only small, Rafferty says she could see the potential for Donna to grow. But she never imagined just how much.
"It has grown well beyond my wildest expectations. I never thought she would wield the kind of power that she does or have the colossal self-esteem that she does."
Donna's bulletproof confidence is awe-inspiring, making her one of the series' best-loved characters. But while Rafferty admires Donna, she says they couldn't be more different.
"I'm just a goofy, self-deprecating person. I'm an actor and I don't think that actors - or at least actors that have lived in the real world and experienced disappointment - can have self-esteem as colossal as Donna's. Having said that, it's so fun to play and it's been really an amazing experience for me to see how people respond to Donna's confidence."
And while that confidence hasn't rubbed off on Rafferty, the actress admits she can occasionally channel her inner Donna.
"Sometimes I'll say something or have a response and I'll break my arm patting myself on the back and say to my husband, 'Oh, that was kind of quick-witted, like Donna.' I'll be so proud of myself."
Likewise, she says, Macht has little in common with his on-screen persona Harvey. A fact which can often lead the pair to ruin takes with their laughter.
"It's funny for us to play these people that we just so aren't. It's funny to be strutting around in these clothes that we don't hang out in."
But she says that real-life friendship has also been an asset on set, particularly in the early days.
"We had a comfort level with each other. You were able to sense that Donna and Harvey had a history together because we did. Sometimes it's a little bit awkward, when you're just meeting someone on the first day, to have that kind of camaraderie."
Six seasons on, that relationship is more solid than ever. The end of season five saw Mike Ross head to jail after he made a surprise guilty plea in his fraud trial.
Pearson Specter Litt was left in tatters as staff fled the troubled firm, leaving just the core cast - including Donna and Harvey - to pick up the pieces.
"The season five ending was pretty incredible and season six we come back five minutes after we left off," says Rafferty. "There's no crazy time jump.
"As you saw at the end of season five, Mike's walking into that prison and we're going to pick up right with him dealing with his intake into that prison. Then we're going to be at Pearson Specter Litt, which is a ghost town. Everyone has split.
"It's time for everyone to circle the wagons and figure out how to get Mike out of jail. And figure out if there is a firm to save. It's pretty high stakes."
Low down
Who: Sarah Rafferty plays Donna Paulsen in Suits When: Season six premieres today Where: On Lightbox