Mad Men star Jared Harris has got engaged.

The British actor, 51, who played uptight advertising executive Lane Pryce in the drama, is set to tie the knot with longtime girlfriend Allegra Riggio.

According to Us Weekly, the star proposed to the TV host with a custom-made engagement ring featuring a heart-shaped diamond in a rose-gold setting, a series of smaller diamonds around the band and an "H" initial for Harris.

Allegra, who met Jared three years ago, confirmed on Twitter: "We're engaged! TeamHarris."

She added that the pair were "giddy and adorable" over the engagement, saying: "Bouncing, floating, giggling, dancing, and merriment are ensuing."

Jared, the son of the late actor Richard Harris, recently appeared in Lincoln, and is currently filming a role as Lucretius in Pompeii.