Actor John Michie has told a jury he begged security staff at a music festival to let him through the gates as his daughter lay dying inside.
He and his wife rushed to the Bestival site after hearing Louella Fletcher-Michie, 24, screeching “like a wild animal” on the phone, a court heard.
Winchester Crown Court has heard she was found dead after taking 2CP.
Boyfriend Ceon Broughton, 29, denies manslaughter and supplying drugs.
The court heard Mr Michie and his wife Carol drove from London to the festival, held at Lulworth Castle, Dorset to get to their daughter.
Giving evidence, the Holby City star wept as he described his efforts to persuade a member of security staff to let him in.
He said he eventually convinced one attendant to take his phone, which had a location pin-drop sent to them by Mr Broughton, while they waited at the entrance.
The couple waited up to 90 minutes before they heard their daughter’s body had been found, he said.
Carol Fletcher-Michie, told the court she heard her daughter repeating phrases in a “horrible voice” as she spoke to Mr Broughton on the phone earlier on 10 September 2017.
“She was like a wild animal in the background. That was the last time I heard her voice. She was screeching,” she told the jury.
The trial previously heard Ms Fletcher-Michie had urged her boyfriend to film her after she had taken the Class A drug.
She was found dead by security guards at 01:15 on what would have been her 25th birthday.
Prosecutors have alleged Mr Broughton failed to seek help because he feared breaching a suspended jail sentence.
In the witness box, Mr Michie described how he had later released a statement defending Mr Broughton, after newspapers reported that a murder investigation was under way.
“I didn’t realise how in the six hours he was with her, he had not taken her to get help, how he had seen her very, very distressed state.
“I believe he even filmed her after she was dead.
“I think Louella loved Ceon. I’m not sure that he loved her
“I don’t know how you could say you love someone if you left them to die in front of you.
“If I was in Ceon’s situation, I would have taken another human being, let alone my girlfriend who I was supposed to love, to a medical tent to save her life.”
Stephen Kamlish QC, defending Mr Broughton, said a lot of what Mr Michie had told the jury was wrong.
“You don’t know for example how many times he told people where he was,” he said.
Ms Fletcher-Michie’s sister, Daisy, told the court how she pleaded with Mr Broughton on the phone to take Louella to a medical tent.
“I couldn’t get any sense of urgency… He didn’t say much at all, just like a really slow, ‘yeah, yeah, ok,” she said.
“There’s no way I can believe in six hours someone [wouldn’t make] their best efforts to get 400m to a medical tent.”
Mr Kamlish suggested the terrain was difficult and Ms Fletcher-Michie was angry at her boyfriend.
“I’m pretty sure a 28-year-old man could overpower her in a desperate situation like that and carry her,” Daisy Fletcher-Michie replied.
Her brother, Sam, recalled how he asked Mr Broughton what drug his sister had taken.
“It was 2CB and he said, ‘but I bumped it up a bit,'” Mr Fletcher-Michie told the court.
He said he did not not understand whether that meant a bigger dose or an additional drug, and he thought 2CB and 2CP were the same thing.
Mr Kamlish said: “You may have thought you heard ‘bumped it up’, but you heard ‘bumped it’,” which the barrister said was a phrase meaning ‘took drugs’.
Sam Fletcher-Michie insisted he had heard correctly.
Earlier, the jury in the case was reduced to 11 after the judge discharged a woman “for personal reasons”.
The trial has previously heard Mr Broughton has pleaded guilty to supplying 2CP to Ms Fletcher-Michie and her friend at Glastonbury Festival in 2017.
The trial continues.