But whoever it is, Mackie's promise suggests he won't get paid more than Colman.
Producers point to Smith's starring role in "Doctor Who" - he played the sci-fi hit's Eleventh Doctor from 2010 to 2014 - as the reason for him making more than Foy. Foy, in the second season alone, had to put up with 120 costumes and the endless fittings and fuss that come with them.
While Smith certainly had more star power when he was cast - having previously starred in United Kingdom series Doctor Who - Foy's quickly rose over the span of the first season.
The producers of hit TV series The Crown have confirmed Helena Bonham Carter will be joining Olivia Colman for the third season of the show.
The Crown co-producer Suzanne Mackie told a television industry conference in Jerusalem that the pay difference would be rectified.
Even royals, it seems, may suffer from the gender pay gap.
Foy, on the other hand, had only appeared in smaller British dramas before winning The Crown's main role.
She also won an Emmy for outstanding lead actress in a drama for the first season. So, for that matter, has Smith, 35, and nearly the entire cast. "Going forward, no one gets paid more than the Queen", she said. Foy not getting equal pay on a show where her character and Smith's are constantly fighting about him feeling emasculated by her power is so deliciously poetic I could nearly laugh. So it makes the decision to pay her less than Matt likely all the more confusing.
Foy's agent did not immediately respond to a request for comment on Wednesday.
Earlier this year actress Michelle Williams was paid a fraction of what her All The Money In The World co-star Mark Wahlberg earned for the movie's reshoots.