He is married to Hollywood actress Emma Thompson, with the couple tying the knot in 2003 and sharing two children.
Their daughter Gaia, 21, was born four years before they got married and, the same year they cemented their martial nuptials, the Greg and Emma adopted Tindyebwa, 33, a Rwandan orphan and former child soldier.
Arguably best known for his role as John Willoughby in the Oscar-nominated 1995 adaptation of Jane Austen’s Sense and Sensibility – the film on which he met his wife Emma – Greg has a distinguished acting career.
Prior to meeting Emma he actually dated one of her close friends, the Hollywood actress Kate Winslet.
Emma was married to Kenneth Branagh at the time but when they split in 1995 the door was thrown open for a romance to blossom with Greg.
Born in Newcastle, Greg was educated at the Heriot-Watt University in Edinburgh, where he studied architecture.
But it was when he studied drama at the Royal Scottish Academy of Music and Drama that he really discovered his passion for acting.
Acclaimed stage appearances were followed by breaks in a string of BBC period dramas including The Moonstone – featuring actress Keeley Hawes – as well The Buccaneers, Madame Bovary, The Riff Raff Element and Cranford.
Greg also starred as the character Marshall in ITV’s successful seven-part drama Wonderful You and dazzled in an adaptation of the classic Thomas Hardy book Tess of the d’Urbervilles.
He turned his hand to producing in 2010 when he worked on the BBC’s production The Song of Lunch, which starred his wife Emma and the late Alan Rickman.
Six years ago Greg impressed as the emotionally-distanced father Gilbert Aldridge in the Beeb’s gripping two-part adaptation of Sadie Frost’s debut novel The Outcast.
And two years ago he became a household favourite as a surprise winner of a celebrity edition of The Great British Bake Off in aid of Stand Up to Cancer.
Now it’s time to swap his acting skills for the ballroom floor.
And Greg has revealed he is dancing in honour of his late sister who sadly died five years ago.
“My beautiful sister was a huge disco queen,” revealed Greg.
“She left our world almost exactly five years ago in a glitter ball coffin. This is for her. My gorgeous Diva sis, who would have been insane with excitement that her little bro was doing this.
“I will channel her, as her bro can’t dance – but I’m thrilled to be dipping my toes, knees, hips and arms into this wonderful world, and hope to make her proud, and obviously make her laugh.”
Greg joins a string of celebrities including McFly’s Tom Fletcher, Peep Show star Robert Webb, presenter AJ Odudu, Great British Bake Off winner John Whaite, CBBC host Rhys Stephenson, Dragon’s Den star Sara Davies, actress Katie McGlynn, BBC Breakfast host Dan Walker and presenter Tilly Ramsay on this year’s eagerly-anticipated show.