The series stars Luther's Warren Brown as Jack Quinn, leader of an elite team of mavericks who bring criminals to justice - by any means.
Harewood and Nuttall join fellow guest stars Honor Blackman (Goldfinger) and Nick Moran (Lock, Stock and Two Smoking Barrels).
"I'm so excited to be part of this gripping new drama," said Nuttall. "Being on set with the fantastic cast and crew was really fun.
"My character is a hard-hitting journalist - very different from some of the other characters I've played - which was lots of fun!"
Keith Allen (Robin Hood), Neil Maskell (Utopia), Kate Dickie (Game Of Thrones) and Michael Maloney (The White Queen) will also appear in the show, from writer Tony Jordan (Life On Mars, Hustle).
> Warren Brown, Andrew Lee Potts for BBC One's By Any Means
Shelley Conn (Terra Nova), Andrew-Lee Potts (Primeval), Gina McKee (Line of Duty) and Elliot Knight (Sinbad) join Warren Brown as regular cast members.
"We're delighted to welcome such an extensive and talented list of guest stars to By Any Means, accompanying our wonderful main cast," said Belinda Campbell, Executive Producer for Red Planet Pictures.
"There are some brilliantly crafty and manipulative characters throughout the series, which have been expertly brought to life by these gifted actors and actresses."
Series star Brown recently told Digital Spy that By Any Means is "like The A-Team meets The Equalizer".
"It is serious, but there's a lot of fun to be had in it, as well," he explained. "It's quite caper-ish and there's a lot of banter between the team."
> Luther Warren Brown: 'A film prequel would be fantastic'