FORT LAUDERDALE, Fla. (AP) _ Blockbuster Entertainment Corp., the video store operator, will acquire 48.2 percent of Spelling Entertainment Group Inc., a television producer and distributor.

Fort Lauderdale-based Blockbuster said Monday it would gain 24.5 million shares of Spelling's common stock in a trade with American Financial Corporation, a Cincinnati-based insurance and investment holding company. The shares represent American's entire stake in Spelling.

Blockbuster will give approximately 7.6 million shares of its common stock to American. In addition, the company will issue to American Financial warrants to acquire two million shares of Blockbuster common stock at an price of $25 per share.

''We are excited about this opportunity for Blockbuster to become a major force in the distribution and production of filmed entertainment,'' said H. Wayne Huizenga, chairman and chief executive of Blockbuster.

''The Spelling Group is a leading company in the entertainment business with an enormous library of programming available for both domestic and international distribution,'' Huizenga said.

Los Angeles-based Spelling Entertainment Group, a top producer since the 1970s, has a library that includes TV series, feature films, television movies, mini-series and specials.

The library includes more than 55 former network series such as ''Little House on the Prairie,'' ''The Love Boat,'' ''Dynasty,'' ''Dallas,'' and ''Twin Peaks,'' and a selection of feature films including ''Basic Instinct,'' ''Total Recall,'' ''Terminator 2,'' ''Platoon'' and the ''Rambo'' trilogy.

Spelling Entertainment is the producer of the hit network series ''Beverly Hills, 90210'' and ''Melrose Place'' as well as a number of made-for- television movies.

Blockbuster's video division included 3,127 video stores as of Dec. 31, 1992 in 48 states and nine foreign countries. Of those stores, 1,125 are franchise-owned and 2,002 were company-owned. Its music division includes 238 Sound Warehouse and Music Plus stores in 40 U.S. cities.