Mad Men actor Jared Harris is engaged to marry his girlfriend of more than three years, TV host Allegra Riggio Credit: Stefanie Keenan/Getty Images

Life after Mad Men is proving to be pretty sweet for Jared Harris. The 51-year-old actor -- who played Lane Pryce on the AMC series until last season -- is engaged to marry longtime girlfriend Allegra Riggio, his rep confirms to Us Weekly.

The star proposed to TV host Riggio on Sunday, June 2, with a custom-made engagement ring by Erica Courtney. The stunning sparkler features a heart-shaped diamond in a rose-gold setting, with smaller diamonds placed around the band and an "H" initial on the gallery (for "Harris").

Riggio, who met her British beau a little more than three years ago, confirmed the couple's happy news on Twitter. "We're engaged!" she announced happily. "#TeamHarris."

Later, the beautiful bride-to-be responded to fans on the social-media site, gushing that she and her groom were "giddy and adorable" over the engagement. "Feeling SO MUCH love today!" she wrote on Tuesday, June 4. "Thank you guys for your well-wishes! So happy."

"Bouncing, floating, giggling, dancing, and merriment are ensuing," she added.