Lord Bath has died at the age of 87 after contracting coronavirus.
Longleat, the park and home he ran, announced on Twitter the 7th Marquess of Bath died on Saturday at the Royal Bath United Hospital.
He was admitted there on 28 March where it was confirmed he had the virus.
In the statement, his family appealed for privacy and thanked the medical team which "cared so professionally and compassionately" for him in his final days.
Longleat Safari Park confirmed the news on Facebook, expressing their "deepest sadness" at his death.
It added: "The family would like to express their great appreciation for the dedicated team of nurses, doctors and other staff who cared so professionally and compassionately for Alexander in these extremely difficult times for everyone."
Alexander George Thynn, 7th Marquess of Bath, was born on 6 May in 1932 and grew up in his family's home at Longleat, near Warminster in Wiltshire.
He was known for his flamboyant style of dress and for having relationships with women he often referred to as his "wifelets".
Tributes have been paid on Twitter, including from Piers Morgan, who described him as "one of Britain's most colourful characters".
Ben Fogle, who filmed TV series Animal Park at Longleat about the lord's estate, said he was "devastated", while the show's present Kate Humble said she was "very sad".
She tweeted: "Everyone will describe him as eccentric - and he was, gloriously so - but he was also kind and fun - and we all need a bit of kindness and fun in our lives."
BREAKING: Lord Bath, the eccentric & ebullient owner of Longleat Safari Park, has died of coronavirus, aged 87. One of Britain's most colourful characters - very sad news. pic.twitter.com/OuxwpqAoWD— Piers Morgan (@piersmorgan) April 5, 2020
Very sad to hear about Lord Bath of @Longleat. Everyone will describe him as eccentric - & he was, gloriously so - but he was also kind & fun - & we all need a bit of kindness & fun in our lives.— Kate Humble (@katehumble) April 5, 2020
Lord Bath was involved in politics and stood in the very first European parliamentary elections in 1979, representing the Wessex Regionalist Party which he helped to found.
After inheriting the Marquess seat in 1992, he then sat as a Liberal Democrat in the House of Lords but lost his seat when Labour reforms excluded most hereditary peers.