The 'Best Song Ever' singer turned 20 on Thursday (29 August), but rather than a day off, he joined his 1D band mates in East London for a spot of filming at a pie and mash shop.
Joining Liam was his new girlfriend Sophia, who held his hand as they walked down the street.
Liam confirmed earlier this month he is dating old school friend Sophia, who was a classmate of his at St. Peter's Collegiate in Wolverhampton.
The pair took their romance public after the One Direction movie premiere on 20 August, when they were snapped holding hands as they arrived for the after party at the Sanderson Hotel.
After the This Is Us premiere, Liam appeared to hit out at internet trolls criticising Sophia, tweeting: "Always sad to get on here to read horrible stuff about someone you care about…"
On a happier note, Liam tweeted this morning: "Good morning everyone :) can't quite believe my life there's no bigger birthday present than what you've done for me in 3 years thank you."
And, backing that statement up, today also marked the day This Is Us is released in cinemas! Fans will be able to get a glimpse of the everyday lives of 1D in their first feature-length documentary.
One Direction are just back in the UK following a successful whirlwind trip to the States where they picked up a gong at the MTV Video Music Awards and premiered their movie in New York.
They also found a rather famous (okay, very famous) fan in Lady Gaga, who was quick to defend the boys against claims a minority of the audience at the VMAs booed when they arrived on stage to accept their award.
Gaga tweeted at 1D: "You know what @onedirection ? Your fans REALLY love you, and it's beautiful to see! Enjoy your Moonman! Love, Seashell Girl *winks*."
Liam replied: "Thank you very much as to you and your fans both really are some of the best congrats on a great performance."
Watch a trailer for This Is Us below: