By Aaron Saldanha

LONDON (Reuters) - Shares of AMC Entertainment and GameStop gained on Friday, on track for a strong end to a spectacular week, which has already seen the movie theater chain's market value double as retail traders stormed back into meme stocks.

AMC's shares were up 17.3% to $31.11 in U.S. premarket trading on Friday, while those of video game retailer GameStop were 2% higher. GameStop, which was at the heart of the so-called "stonks" retail trading mania this year, is set for its best weekly gain since mid-March, up more than 43% so far.

Retail traders' shift into so-called meme stocks - shares favored by the denizens of online communities - comes on the back of a selloff in Bitcoin and other cryptocurrencies whose prices have slumped in recent weeks.

Data shows the cinema operator AMC's scrip has been the most traded stock on brokerage Robinhood's popular trading app, as well as on that of UK-based Freetrade, where buy orders have outnumbered sell orders two-to-one.