Hunger Games star Liam attended the film's world premiere in the capital's Leicester Square on Monday evening (2 September) and was later spotted arriving for the glitzy after party.
The 23-year-old jetted into London at the weekend, a week after his fiancée Miley Cyrus, 20, got tongues wagging (mostly her own) with a raunchy performance at the MTV Video Music Awards 2013.
Miley wasn't with him at the premiere, not that that's surprising. The duo rarely make public appearances together: their last red carpet as a couple was on 8 August at the premiere of Liam's movie Paranoia; the one before that was June 2012.
Former Hannah Montana star Miley is also in the middle of a promotional blitz in the US ahead of her new album Bangerz.
Nevertheless, rumours have been floating around that Liam wasn't too pleased with Miley's racy VMAs appearance alongside Robin Thicke but we'll point out neither he nor Miley have commented, and Liam was spotted visiting Miley's parents' house in Toluca Lake, California a few days after the show.
Miley and Liam met on the set of romantic drama The Last Song back in 2009. After three years of dating, Liam popped the question with a 3.5-carat diamond ring from Neil Lane on 31 May 2012.
Since then, their romance has been plagued by break up rumours. In May, a source told People magazine the couple were very much still living together but had just pushed back wedding plans, meaning Miley could focus on her new music.
Watch a trailer for Rush below: