Sideshow: Kutcher and Kunis engaged

Art imitates life, right? Or is it the other way around? Well, never mind. What we're trying to say is that Ashton Kutcher and Mila Kunis, a couple on That '70s Show, are a couple in real life, reports Us Weekly on its website.

Kunis was spotted out shopping in Los Angeles Thursday and sporting an appropriate rock on the third finger, left hand. A source confirmed the betrothal to Us later in the day.

"The ring is tasteful," said the source, weighing in at 5 to 6 carats. The engagement won't be a long one, the source disclosed.

"He wants to marry her soon and start their life together," confided a Kutcher bud. "He was planning this all along." The couple began dating about two years ago. Kutcher, 36, who took over for Charlie Sheen on Two and a Half Men, is divorced from Demi Moore and starred last year in the movie Jobs.

Kunis, 30, is keeping busy in the movies, including Ted, Black Swan, and Forgetting Sarah Marshall, and TV's Family Guy.

Us Weekly, which may be cornering the market on celebrity engagement announcements, informs the world that former child star Mary-Kate Olsen, 27, is engaged to banker Olivier Sarkozy, 44, her boyfriend for almost two years. This Sarkozy is the half-brother of that Sarkozy, Nicolas, former president of France. Once again, the information comes from sources. It will be Mary-Kate's first trip down the aisle and Sarkozy's second.