"She was a wonderful woman and actress and treated me like I was her own," Lohan's statement read. "I didn't see much of her over the years but I will miss her. My heart goes out to her family. This is a tragic loss."
On ABC's "The View" Wednesday, Barbara Walters and her co-hosts spoke about their admiration of Richardson and her family.
Walters described Richardson as "lovely" and as a good friend of the show, on which she has appeared more than three times.
"She's beautiful," said Walters.
"The Redgraves are the most wonderful family," said co-host Joy Behar. "They mind their own business, they're talented, they're smart and they love their family."
"Our thoughts and hopes are with the family and with Liam and Vanessa," added Whoopi Goldberg.
Richardson was a member of one of Britain's most famous acting dynasties. She was the eldest daughter of Oscar-winning actress Vanessa Redgrave, 72, and director Tony Richardson.