In fact, the 43-year-old actress’s career has gone from strength to strength, with starring roles in dramas such as Red Cap and Hotel Babylon, and a critically acclaimed performance in the West End revival of 1960s musical Sweet Charity. She’s even branched out into film work, with a part in period drama Great Expectations (2012), opposite Helena Bonham Carter.
But in the past year, it’s been Tamzin’s personal life, rather than her acting career, that has been in the news.
In September 2013, she filed for divorce from her husband of seven years, fellow actor Tom Ellis, citing adultery, after he confessed to a one-night stand while filming in the US. Despite attempts to patch up their relationship, the divorce was finalised earlier this year.
Tamzin has admitted that it’s been an extraordinarily tough period of her life, but, with the help of her family and friends, and for the sake of the couple’s two young children – Florence, six, and Marnie, who’s about to turn two – she’s beginning to look to the future.
She’s the subject of an episode of BBC1’s Who Do You Think You Are? in August, followed by her first full run of New Tricks, the BBC1 drama series about a group of ex-police officers investigating unsolved crimes.
Tamzin joined the successful drama for the final two episodes of series 10 last year, replacing Amanda Redman who had played DCI Sandra Pullman for a decade. Large shoes to fill, particularly given the programme’s popularity, regularly pulling in audiences in excess of eight million.
“There’s a certain pressure coming into something so big,” Tamzin told the Daily Express. “I don’t know many other drama series that have been going so long. Because of that, you want to add to it and be a credit to it. It makes you up your game. You have to bring something different.”
At the close of the last series, Tamzin’s character, DCI Sacha Millard, the new head of the Unsolved Crime and Open Case Squad (UCOS), found herself desperately trying to win the respect of her new team.
And, rather ironically given the actress’s recent personal problems, her character found her home life imploding, when she caught her Met officer husband with another woman.
“At the beginning of this series, we see Sacha trying to throw herself into work as a distraction. But it’s hard because her ex-husband is her boss and still works in the same building as her.
“She’s not over him and to make matters worse he’s abusing his power, muddying the water and playing games. It’s a really interesting one to play.”
Tamzin wasn’t the only new cast member to join last series. Only Fools And Horses’ Nicholas Lyndhurst (Danny Griffin) replaced Alun Armstrong (Brian Lane) meaning the only original detective left in the line-up is Dennis Waterman (Gerry Standing).
The current New Tricks cast is completed by Denis Lawson (Steve McAndrew), who joined in 2012 to fill the shoes of the departing James Bolam (Jack Halford).
It’s a casting reshuffle that’s appeared to work if the strong ratings are anything to go by.
“It’s the same show but with a different energy,” says Tamzin. “It’s a fantastic cast and I absolutely adore them. I laugh every day and we take the mick out of each other relentlessly.
“As a mum, I’m often sleep deprived when I come into work, and I rely on Mr Lyndhurst’s jokes to get me through the day!”
For a show that mixes crime with a touch of comedy, the scriptwriters have played with some particularly dark subject matter in the next series.
“There are moments when I find myself welling up,” says Tamzin. “As a policewoman, I wouldn’t necessarily be crying at this moment but I can’t help myself.”
Thankfully, it’s not all tears and traumas. Tamzin admits she’s been having a whale of a time performing her own stunts.
“The more action the better for me. I love the excitement of it,” she says.
New Tricks series 11 is expected to air on BBC1 later this year.