The £10 million Aspen ranch, called Wildcat Lake, is where Douglas proposed to Zeta-Jones on New Year's Eve three years ago. Insiders say the couple have decided to sell because they are spending less time there. They also have apartments on New York's Park Avenue and in Beverly Hills, a house in Bermuda and a mountainside villa in Majorca. The couple also recently submitted plans to expand a house in the Welsh seaside resort of the Mumbles, where the actress grew up.
Estate agent Tim Cottrell, who calls them "a charming couple", says the Aspen property includes a barn with stables, and a private lake. Douglas, 58, bought 6,700 acres around the ranch 12 years ago and has developed it into an exclusive getaway, boasting holiday homes and a 50-acre lake stocked with trout. It has a herd of elk, with hunting banned to keep it as a wildlife sanctuary.
Kevin Costner, Jack Nicholson and Goldie Hawn are neighbours and, at the height of the ski season, the local Aspen airport is clogged with private jets. Even a modest home there costs well over £1 million.
The Douglas ranch is protected by a security gate and hidden deep in a valley. " Security is not an issue," says Mr Cottrell. "You wouldn't know it was there." It has miles of private cross-country skiing routes and the slopes of Aspen can be glimpsed from the front door.
Zeta-Jones inherited the decor of the ranch from Douglas's first wife Diandra and was asked if she wanted to redecorate. But as she told Vanity Fair magazine: "I don't really care. I don't have to make my stamp with material things."
The birth of Carys, a Welsh name meaning "love" comes hot on the heels of Catherine's triumph at last month's Oscars, when she won the award for best supporting actress. Eight months pregnant at the time, she had to be helped to her feet by her husband to collect the trophy. Earlier in the ceremony, she delighted the audience by performing a routine from Chicago with co-star Queen Latifah.