It comes following speculation the pair have enjoyed a string of secret dates
The pair were pictured cosying up in the stands as the Seattle Seahawks beat the New England Patriots at Levi's Stadium in San Fransisco.
It is believed the couple shared a suite in the stadium, which caught the attention of other high-profile celebrities in attendance.
"There were crowds of staff trying to catch a glimpse of them," a source told the US Sun.
"At one point Lewis walked down the corridor and shortly after Kim followed him shortly after.
"His eyes were straight on her in a protective way and they were in a big group hugging and kissing people."
The stars are said to have started dating last month, and were seen sharing a night at the Estelle Manor in the Cotswolds, which costs upwards of £1,000 a night.
The couple were protected by security as they were given exclusive use of the spa, before having a meal in a private room on that occasion.
Following the Superbowl appearance, Lip reading expert Nicola Hickling told the Daily Mail that Lewis could be seen to tell Kim about meeting his mother.
He reportedly said something on the lines of: "No I don’t take just any girl to my mom, I mean you’re gonna meet someday." Kim then was said to reply "OK" as she made her way to the exclusive seat.
They watched on the New England Patriots and Seattle Seahawks collide in a rematch of the 2015 Super Bowl, with the Seahawks emerging 29-13 victors.
They previously spent time together at the at the Wall Street Journal’s innovator awards, where Kim was celebrated for her lingerie firm Skims – valued at £3.6 billion.
They were also said to have enjoyed a New Year's Eve party, thrown by Kate Hudson in Aspen, Colorado, but the pair left separately.
Kim and Lewis previously met on the celebrity circuit and were pictured with their then partners, Kanye West and Nicole Scherzinger, in 2014 at the GQ Men of the Year Awards in London.
Lewis was a good friend on Kanye's, even spending Easter with their family in 2015 and bonded over music.
Kanye said: "Lewis Hamilton’s over at my house and we’re playing some music in my studio.
"We’re having an Easter brunch and all of the family’s there, my wife’s family, my friends, everything.
"And everybody’s like 'What is this music?’ And I'm like, 't’s Lewis Hamilton’s music.'
"They’re like, ‘Oh my God. It’s really good."
