Marks & Spencer used its official Twitter account to tweet out pictures of babies alongside a number of "royal etiquette guide" rules, including "one may greet a lady with a light kiss on the cheek, only if one has been formally introduced".
Supermarket giant Tesco, which launched a baby care brand called Tesco Loves Baby in January, is collecting advice for life with a newborn through its @TescoBabyClub Twitter account and will publish the best tweets in a "beautiful baby book", which it claims it will send to the royal couple.
Meanwhile, babycare specialists Mothercare and Kiddicare have gone head-to-head with similar royal baby takeovers of their Facebook pages (see gallery).
Both brands have changed their Facebook homepage background images to include a baby wearing a crown, alongside a message congratulating Kate and William.
Seraphine, the upmarket maternity clothing brand, continued its outdoor bus campaign. The first execution, which broke earlier this month, asked: "Is it a girl? Is it a boy?".
From today, the ads created by JWT London, now read: "Congratulations M’um", in a play on the regal Ma’am salutation.
Babycare product manufacturers are also getting in on the action with Johnson & Johnson publishing a "for all royal babies" post on its Facebook page, while Unilever is preparing to roll out commemorative royal baby packs of Comfort and Persil.
However, brands jumping on the back of the royal baby news has not been received well from all quarters, as evidenced by messages left on the Johnson & Johnson post.
Facebook user Alison Johnson said "ooh boy, look at all the advertisers racing to jump on the bandwagon :-(", while Anna Williams Hughes complained, "didn’t take Johnsons [sic] long to cash in then".