He looked like any other father, treating his two daughters to a day out at the Epic Universe theme park in Orlando, Florida.

Wearing an oversized red Mario T-shirt and sagging Stone Island tracksuit bottoms, actor David Harbour, 50, – whose marriage to singer Lily Allen ended in December last year – sported a bucket hat, while the teenage girls wore Super Mario headbands with green and red mushrooms for ears.

In a video posted on Saturday, they are seen walking around the crowded Universal Orlando resort, chatting to fans and trying out the rides.

Yet the Daily Mail can reveal the girls were none other than Allen’s daughters Ethel, 13, and Marnie, 12, by her first husband, builder and decorator Sam Cooper. On the very weekend Lily was releasing an album now widely thought to be an attempt to publicly humiliate Harbour and his role in the breakdown of their marriage, he was looking after her children.

It is an astonishing turn of events. After all, in track after semi-autobiographical track, the album reveals details – or at the very least hints at them – which cast Harbour as an unsupportive husband, cheat and ‘sex addict’. At its heart is a character called Madeline, who is alleged to have had a secret relationship with him.

David Habour stops for a picture with a fan while wearing a red Mario T-shirt during a day out at the Epic Universe theme park in Orlando, Florida, with Lily Allen's daughters

David Habour stops for a picture with a fan while wearing a red Mario T-shirt during a day out at the Epic Universe theme park in Orlando, Florida, with Lily Allen’s daughters

Ms Allen and Harbour with her daughters Marnie Rose Cooper and Ethel Cooper at the Stranger Things 4 premiere in 2022

Ms Allen and Harbour with her daughters Marnie Rose Cooper and Ethel Cooper at the Stranger Things 4 premiere in 2022

The album, West End Girl, is proving a major triumph for Allen, 40. In all, the songs have been streamed more than eight million times worldwide on Spotify since it was released on Friday, while the album already sits at the top of the UK iTunes album chart.

No doubt the real-life drama it allegedly describes is driving its success. Allen’s first body of music in seven years tells a sordid tale of sexual betrayal, which has led her legion of fans worldwide to brand the actor ‘evil’, ‘sickening’ and ‘the worst kind of man’ online.

If the relationship ended in public recrimination, however, it began as a dream come true for the singer.

A year after they met in 2019, the pair wed in Las Vegas, joined only by Ethel and Marnie. Allen shared pictures of her daughters celebrating with their new stepfather, eating hamburgers outside the chapel.

But, as she alleges in the ‘tell-all’ album, it was when she landed a role on the West End stage in 2021 that the marriage began to falter. Indeed the lyrics of the first song West End Girl strongly suggest Harbour was not supportive of her new career as a stage actress in the play 2:22 A Ghost Story. Around this time, it’s thought Harbour asked for an open marriage, but eventually ‘broke the rules’ and cheated on her.

Now public enemy number one to many, Harbour has gone dark online and switched off the comments on his social media. But despite internet sleuths imagining him holed up in his Brooklyn apartment cowering with shame, he is apparently not hiding at all, but treating the children of the woman who is publicly vilifying him to a jolly day out.

A source who knows Allen well told the Daily Mail: ‘This is typical Lily. She opens her mouth and totally lambasts someone, and meanwhile he’s looking after her children.

‘She has told people what she wants them to hear, in interviews and song lyrics, which means she has come across as the victim.

‘But she hasn’t told the full story. Again, typical Lily. David spent several years as Ethel and Marnie’s stepfather. It’s lovely to see they, at least, still have a relationship. You just wonder why Lily would feel the need to attack David so much and make him look like the worst man in the world when actually he’s caring for her daughters.’

Harbour, who has no children of his own, was reportedly not keeping a low profile but chatting to fans at the theme park as he accompanied the girls and a group of their friends.

One person commented on a video of the group at Epic Universe: ‘We met him today and he was cool about us saying hi and had a quick exchange with us.’

Another fan added: ‘So he’s there with Lily’s children while she promotes an album.’

On Thursday, the night before West End Girl was released, the actor was also spotted at the Madison Square Garden arena watching the New York Rangers play ice hockey. Social media comments hint that Ethel and Marnie were there too, but it cannot be confirmed.

Meanwhile, Allen has been celebrating the release of West End Girl, recorded in Los Angeles over 16 days in December last year, by giving various interviews in the UK discussing Harbour and her daughters. When asked by British Vogue earlier this month if Harbour would continue to be a stepparent to her two daughters in the wake of their acrimonious separation, she said: ‘You’ll have to ask him.’

She also told the magazine: ‘There are things that are on the record that I experienced within my marriage, but that’s not to say that it’s all gospel. It is inspired by what went on in the relationship.’

Her daughters appear on the album too.

On the track Relapse, Allen describes how Harbour made ‘a f****** mess’ as she tried to be a ‘modern wife’, but struggled with their open marriage and life in America. According to the song, none of this provided a good role model for the girls.

Ms Allen and Harbour at the 2022 Met Gala celebrating In America: An Anthology Of Fashion

Ms Allen and Harbour at the 2022 Met Gala celebrating In America: An Anthology Of Fashion

Perfect Magazine's new cover story today featuring Ms Allen who, after 7 years, is returning to music with her new album West End Girl

Perfect Magazine’s new cover story today featuring Ms Allen who, after 7 years, is returning to music with her new album West End Girl

‘The girls are looking at me to teach them all about love, But I can’t seem to hold my s*** together long enough,’ she sings. And Allen details how she battled to maintain her sobriety. ‘I need a drink. I need a Valium. You pushed me this far, and I just need to be numb.’

In another track, Let You Win, Allen speaks about shielding the girls from the true nature of her divorce from Harbour.

She sings: ‘Don’t tell the children, the truth would be brutal, your reputation’s unstained.’

Later she adds: ‘Lie to the children the ending was mutual, I’ll shoulder all of the pain.

‘I’m sick of carrying, suffering for your sins. Already let you in, so why should I let you win? You’ve taken everything.’

Harbour rose to prominence in 2016 playing the burly detective Jim Hopper in the sci-fi horror series Stranger Things – a reliable and paternal figure to Millie Bobby Brown’s character Eleven. But on Allen’s podcast Miss Me? – before the split – he admitted he ‘never wanted kids’ before meeting her.

Recalling the time he first met her girls, he said: ‘I was scared but almost immediately, I fell in love with them.

‘It was that feeling people talk about when they have kids, you want to take care of them, give them anything.’

Over the years, Harbour said that he grew into his role as a caring and hands-on stepfather, helping with everyday tasks such as packing luggage for summer camp and driving them long distances when Allen’s plans changed.

He called being a stepfather ‘the most surprising and enjoyable thing’ he had ever done.

‘There was just an immediate love for them that was so unique,’ he said. ‘They were innocent, little faces looking up at me, and that really pushed me over the edge. I realised this is a family, a pre-made family, and I want to be there for them.’

And amid all of her hatred towards him, which is made apparent in the 14-song album, Allen has also praised Harbour for the life he provided her daughters.

It’s been almost a year since their marriage crumbled, but she said earlier this month, ‘My kids had an amazing experience living in America for five years, and I have a lot of compassion for my ex-husband.

‘I think we all suffer.’