Courteney Cox, that little real estate minx, has surreptitiously acquired a second condo in the star-stacked Sierra Towers building at the Beverly Hills end of the Sunset Strip. The whole deal went down on the down-low — meaning the condo was not listed on the open market — but property records show that the sitcom queen shelled out $2.5 million for the high-floor one-bedroom and 1.5-bathroom apartment that opens to a wide, mountain-view terrace.

The new condo sits right next door to the somewhat bigger, nearly 1,700-square-foot spread Miz Cox picked up for $2.05 million in September 2011, nearly a year after she and her ex-husband David Arquette publicly announced their split. Other high-profile peeps who own at Sierra Towers include Bruce Makowsky, David Bohnett, Matthew Rolston, Joan Collins, Diahann Carroll and Judith Regan.

Miz Cox also owns a bluff-top compound in Malibu she picked up in early 2007 for $17.15 million. Her ex-husband, who sold the erstwhile couple’s architecturally pedigreed pad in Beverly Hills to DJ-music producer Dr. Luke earlier this year for $18 million, recently dropped $7.15 for a historic mansion in L.A.’s Hancock Park area.