The musical, which broke the record for the most Golden Globe awards with seven, has also been nominated for 11 Bafta awards, including best film.
The record opening weekend takings for a musical was the £8.12m paid to see Les Miserables when it opened in 2013.
Assassin's Creed, the most popular film last weekend, dropped down to fourth behind Rogue One and Moana.
UK box office top five (13-15 January 2017) |
1. La La Land - £6.6m |
2. Rogue One: A Star Wars Story - £1.8m |
3. Moana - £1m |
4. Assassin's Creed - £950,000 |
5. Passengers - £783,000 |
La La Land stars Ryan Gosling as a jazz pianist and Emma Stone as a hopeful actress who are both trying to fulfil their dreams in Los Angeles.
They each won individual awards in the Golden Globes with the film itself scooping the best motion picture (comedy or musical) prize.