The Liverpool footie star, 25, gave the 23-year-old daughter of actor Jude Law a lift as they modelled Guess Jeans in a new deal as brand ambassadors.
The Sun revealed their growing romance last month.
It came as England skipper Harry Kane gave a Three Lions roar with Phil Foden and Ivan Toney in the team’s official Euros 2024 portraits.
Real Madrid are keen to snap Trent up and he is all set for a starring role in the Euros after limited game time at previous tournaments.
And actress-model Iris, who shaved her head for a role in Danny Boyle’s Sex Pistols drama Pistol, made an eye-catching appearance at the Cannes film festival last month wearing a sheer white mini-dress on the red carpet.
The couple have been taken on as ambassadors by Guess to promote its new Airwash jeans, a greener version of the stonewash denim it introduced in the 1980s.
A spokesman said: “Trent Alexander-Arnold and Iris Law embody the modern evolution of the brand.”
Iris and Trent met while filming on a shoot with Guess.
A fashion insider said: “They hit it off immediately, swapped numbers and started to follow one another on Instagram.
“Since then they’ve been regularly WhatsApping and getting to know each other.”