Hugh Bonneville said his W1A character will prioritise work over romance in the upcoming third series of the BBC comedy.
The show, which spoofs the internal workings of the corporation, is returning this month.
Bonneville’s character – head of values Ian Fletcher – is the object of colleague Anna Rampton’s affections but the actor insisted his work will always take precedence.
He said of Fletcher’s romantic outlook: “This is an area, like that of photographs of lost pets, that Ian keeps close to his chest.
“While certainly romance is something he would consider, really the job comes first.
“It would be unprofessional of him to spend time in the engine room when really his role is to be on the bridge avoiding icebergs.”
Bonneville, 53, said Anna’s storyline is one of his favourites.
He said: “The escalating crisis within the mind of Anna Rampton is a great thread to follow. We know her as an ice maiden but somewhere inside there is a 14-year-old panicking to get out.
“The lengths she goes to put herself in Ian’s path, particularly when he has his cycling outfit on, is very funny.”
The actor has played the character for five series – in predecessor series Twenty Twelve as well as W1A.
In the new series, it is the year of charter renewal and a critical time for the BBC.
Another new challenge comes in the shape of a Channel 4 documentary about cross-dressing ex-Premier League footballer Ryan Chelford (Ben Batt), which alleges the BBC rejected Ryan as a potential pundit on Match Of The Day because of his unconventional private life.
Bonneville said the show has been so popular because viewers can identify with the characters and situations.
He said: “Some people misconstrue it as a satire about the BBC. It’s not, any more than Twenty Twelve was a satire about the Olympics.
“It’s actually just a framework for seeing characters who are, on the whole, incapable of achieving what’s in their job description.
“Some of the characters are idiots, some are endlessly doing battle with idiots – and I think we can all identify with those situations, whether we’re on the fundraising committee for the village cricket pavilion or in President Trump’s cabinet.”
:: W1A returns on September 18 at 10pm on BBC2.