Lily Allen has revealed yet more details of the moment she and Liam Gallagher had sex in plane toilet.

The incident, which occurred during a flight to Japan’s Fuji Rock Festival in 2009, happened while Gallagher was still married to his now ex-wife Nicole Appleton.

Now, writing in her new book ‘My Thoughts Exactly’, Allen explained: “We got hammered on the plane. At some point Liam and I found ourselves together in the toilet doing something that he shouldn’t have been doing, and it wasn’t drugs. Then we were in a lie-down bed together.”

After the flight, Allen explained that she and Gallagher then made their way to a hotel in Japan: “When we landed in Tokyo, Liam said, in his distinctive nasal twang, “What you doing now? Why don’t you come back to our hotel” . . . I was like, ‘Yeah, OK’.”

Gallagher, who had been married to Appleton for around 12 months when this incident occurred, that explained that his and Allen’s fling must be kept a secret. “It wasn’t until the next day when he said something like, ‘No one can hear about this because of Nic’, that I clocked he was married.

“I knew Noel was married and I knew Liam had been married to Patsy Kensit. That was partly why I fancied him. I’d grown up an Oasis fan. I was 12 when he and Patsy Kensit were on the cover of Vanity Fair as the coolest couple.

“Six months later I was in my car with my driver when the phone rang… It was Liam,” Allen writes in her book. “He sounded awful, like he’d been up all night.

“‘Lil’, he said. “I just need you to get on the phone. I’ve got Nic here. One of your mates is, like, trying to do a wind-up or something and saying that you and me had it off or whatever, and I need you to speak to Nic and say that it’s all bollocks.”‘

Allen, speaking on the phone, claims she said: “Oh, Liam, yes sure, it’s all bollocks. Let’s say it’s all bollocks — of course I’ll tell Nicole that it’s all bollocks if that’s what you want — and not think about it too much or even at all, and then maybe it will go away and not disrupt what really matters: The people we love and rely on.’