Walruses feature in the first episode of Blue Planet II. © BBC NHU
One Ocean, the first episode of Blue Planet II, aired on Sunday night and drew in an average of 10.3 million live viewers.
This beat both the Strictly Come Dancing results show and The X Factor, which had an average of 9.6 and 4.3 million live viewers.
These figures don’t take into account those who watch the programmes via catch-up services, such as iPlayer or ITV+1.
The opening episode of Blue Planet II showcased a range of marine wildlife from around the world, including dolphins, walruses, and even a tool-using tuskfish.
One particular scene – a giant trevally hunting sooty terns – generated a lot of conversation on social media.
The 40kg fish gather in a lagoon in the Seychelles where the terns practice their flying. From beneath the surface, the giant trevallies are able to calculate where the birds will fly, then launch themselves out of the water to catch them.
Blue Planet II is a seven-part series airing on BBC One on Sunday evenings. Pick up a copy of our November issue for a Blue Planet II special supplement.
Read more wildlife news stories in BBC Wildlife Magazine