Harry Potter has been a resounding success for Universal’s theme parks, after the boy wizard helped the company rake in millions of dollars in revenue for the first half of 2015.

Universal’s parent company Comcast, said as part of its Q2 earnings report that theme park revenue year-on-year for the quarter jumped 25.7 per cent to US$773m (€706m, £499m), an increase of US$158m (€137m, £96.8m) compared to 2014’s results.

Comcast attributed the sharp increase to high guest spend and attendance, driven by the roaring success of Orlando’s Wizarding World of Harry Potter – Diagon Alley attraction, which since opening in July 2014 has reportedly already paid off half its cost.

Operating cash flow for the company’s theme parks nearly doubled, jumping 44.9 per cent to US$354m (€323.3, £228.5m), compared to US$244m (€222.8m, £157.5m) in the same quarter last year.

Revenue for the first six months of 2015 jumped 29.2 per cent to US$1.4bn (€1.3bn, £904m), increasing from US$1.1bn (€1bn, £710m) for the same period in 2014.

Comcast executives said that despite the positive results, they don't expect to see the fast-paced momentum of Diagon Alley to continue now that the attraction is a year older, forecasting growth to slow with single digit returns in its next earning report.

Universal continues to invest in its theme parks, with plans for a ‘next-gen waterpark’ in Orlando, a King Kong ride at Islands of Adventure, a new Wizarding World in California and potential new theme parks worldwide. Universal also recently signed a deal with Nintendo for theme park rights.