The former home of Phil Donahue and Marlo Thomas in Westport, Conn., is going on the market for $28 million.

Overlooking Long Island Sound, the home is on tony Beachside Avenue, where residents include billionaire Marc Lasry and until recently, Harvey Weinstein.

The sellers are Andrew Bentley and Fiona Garland, who bought the house from Mr. Donahue, the former talk show host, and Ms. Thomas, an actress, in 2013 for $20 million. Mr. Bentley and Ms. Garland have bought up a number of properties on Beachside Avenue in recent years, including Mr. Weinstein’s longtime home, which they bought from the disgraced movie producer for $16 million in 2018.

The former Donahue house is a shingle-style home built around 2007 by the celebrity couple, according to Annette Coplit, of Coldwell Banker Real Estate, who has the listing with Jenny Bentley of Riverside Realty Group. The house measures about 10,000 square feet and has five bedrooms and an elevator. It sits on 6.5 acres, with roughly 400 feet of frontage on Long Island Sound. A ramp leads from the house to the beach, making it easier to transport canoes or paddleboards, Ms. Coplit said. The grounds also include a tennis court and a stand-alone gym.

The lower level of the house has room for party preparations, and the laundry room has three sets of washers and dryers. “The Donahues must have done a lot of entertaining,” Ms. Coplit said.

After buying the house Ms. Garland and Mr. Bentley renovated the kitchen, adding a backsplash that reflects the property’s water views. They also remodeled the master bathroom, which has a bathtub overlooking the Sound through a square window. They hired architect Roger Ferris to design a contemporary barn and a pool house on an adjacent lot they own, but those are not for sale, Ms. Coplit said.

Mr. Bentley is a commodities trader turned graphic designer, and Ms. Garland is an art historian. The couple live in the former Donahue house when they are in town, but are selling because they own other homes and are not spending as much time in Westport as they envisioned, according to Ms. Coplit.

Beachside Avenue is Westport’s Gold Coast, Ms. Coplit said, an exclusive enclave sought-after for its waterfront access and privacy. “On Beachside, everything that sells is a record for the town,” she said. Mr. Weinstein had owned his home there since the 1990s, when he bought it with his first wife, Eve Chilton.

Phil Donahue and Marlo Thomas.

Evan Agostini/Invision/Associated Press

Mr. Bentley and Ms. Garland declined to be interviewed, but Ms. Coplit said they plan to develop several of the other Beachside properties they own. One of them, a spec house, is slated to hit the market in next few months. Mr. Weinstein’s former home is still standing, she said, but Mr. Bentley and Ms. Garland are developing it into two waterfront properties.

Mr. Donahue and Ms. Thomas, known for the television show “That Girl,” had lived for decades in Westport, owning multiple houses in town.

Ms. Coplit Westport’s rental and sales markets have been “red hot” since March, when the coronavirus pandemic hit New York City. She said the coastal town has become very attractive for New Yorkers looking for a refuge from the virus, leading to bidding wars on homes for sale. “People are flocking here,” she said.