“He is such a gent and led her to a waiting car before leaning in and giving her a kiss.
“When she left, Harry waved her off. Zoe had a massive smile on her face.
“You couldn’t miss the ring on her finger. It is absolutely huge.”
The pair’s public encounter follows earlier claims they had been staying in separate beds during their trip to London, despite being seen holding hands.
According to the Sun, Styles was observed dropping Kravitz at her hotel this week before returning alone to his home, and then collecting her again the following morning.
The couple are said to have spent Christmas together at Styles’ family home before travelling to the Bahamas for New Year.
An insider told the Sun: “Harry and Zoe saw in the New Year together in the Bahamas.
“This one is said to have been extra special and there has been talk among locals that a proposal did take place.”
Styles’ professional schedule continues alongside the attention on his personal life.
After the release of his new record, Styles is now preparing for a tour.
It is set to include shows in Amsterdam, followed by 12 concerts at Wembley Stadium, before continuing to South America and a 30-date residency at Madison Square Garden.
The Sun first reported Styles and Kravitz were dating in August, after they were seen together inside Rita’s bistro in Soho.