Woman who died at Bestival is daughter of ex-Coronation Street star
In a statement, Michie's agent said: "Sadly, I can confirm the tragic death of John Michie's daughter, Louella, at Bestival.
"John and his wife Carol ask that the privacy of their family be respected at this traumatic time."
Police at the four-day music festival were alerted just before 1am on Monday to concerns for the welfare of Miss Michie, from London.
Following a search, her body was discovered in a wooded area on the edge of the site in Lulworth, Dorset.
In a statement, Bestival said: "Following today's news announcement, the team at Bestival are devastated to hear about this tragic news.
"We continue to support the police in their ongoing investigation and our thoughts and prayers are with all the woman's family and friends."
Festival founder Rob da Bank tweeted a link to the statement, which was posted on the festival's Facebook page.
The DJ organises the festival, which took place for the first time on the Lulworth Estate in Dorset this year, with his wife Josie da Bank.
Dorset Police said the 28-year-old man had been arrested "to enable officers to conduct an interview under caution to help establish the full circumstances".
Detective Chief Inspector Sarah Derbyshire said: "Following the discovery of the woman's body we have now launched an investigation into her death.
"We have specially trained officers supporting her family at this very difficult time.
"Inquiries are now under way to establish how she died.
"A post-mortem examination will be carried out in due course and this should give us more of an indication as to the cause of her death.
"We are working closely with the festival organisers and I would appeal to anyone with any information about the incident to contact Dorset Police."
Michie, 66, played Karl Munro in Coronation Street from 2011 to 2013, having previously starred as Detective Inspector Robbie Ross in drama series Taggart from 1998 to 2010.
He currently plays neurosurgeon Guy Self in BBC medical drama Holby City.
Last year, organisers announced Bestival would be moved from the Isle of Wight, where it was previously held, to the Dorset site.
Camp Bestival, which is aimed at families with children and takes place in July, is also held at the wooded country estate.
The line-up for Bestival this year included The XX, Dizzee Rascal, Rag'n'Bone Man, Pet Shop Boys, Wiley and Laura Mvula.
On Sunday, festival organisers were forced to close the main arena, the Castle Stage and Ambient Forest due to high winds.
Bestival was first held in 2004 with acts including Basement Jaxx and Fatboy Slim.
The 2017 event, which featured a giant Kanye West head and a bouncy castle large enough for 100 people, was expected to attract around 30,000 festival-goers.
Organisers are due to hold the first Bestival Bali in Indonesia at the end of September.