Gaga was dressed suitably (or unsuitably, depending on which way you look at it), sporting a collection of seashells and starfish arranged in her voluminous wig, as she feasted in SeaShells Fish and Chip Shop.
Despite her toned physique, which she showed off in a pink bra and a pair of black dungarees, Gaga couldn't wait to tuck into the British speciality, even tweeting about it before she jetted in from New York.
"Once in London I'm headed straight for fish n chips, malt vinegar & brew, just a continuation of todays pizza & ice cream!! #postVMAtreats!" she wrote.
Gaga is in town to headline the first night of the iTunes Festival on Sunday.
The gig marks her first live UK date in almost a year, after having to take time off to recover from hip surgery.
The singer is reportedly spending £500,000 on her 60 minute set, which will comprise only of new music from forthcoming album, 'ARTPOP'.
She tweeted before her arrival: "Off to the UK! I've missed my UK monsters so much! I cannot WAIT to hit the stage at Roundhouse and play you new music!"
Gaga also previously teased that she will unveil one of her new collaborations from the album at the gig.