The 22-year-old was joined by his 30-year-old fiancé Claudia Kowalczyk upon signing his contract with the Gunners.
Kiwior's fiancé, who calls herself 'twerk queen' on social media, has already reacted to the defender's transfer to the Emirates: "So proud. You deserve."
She also had a message to Arsenal supporters, writing on Instagram: "Thank you for all for your messages. I can't reply to everyone, but I really appreciate it. London I'm ready."
Kowalczyk has won Queen of Germany's Twerk Competition in 2017 and was a semi-finalist in the European Twerk Championships in 2018.