Arsenal gave up their training base in Colney for the day to allow National Football League side St Louis Rams to practise ahead of this weekend's match against the New England Patriots.
The Gunners, who lost 2-0 to Schalke 04 in the Champions League last night, were nowhere to be seen when the training pitch transformed into a practice area for the Rams.
The American football side take on the Patriots at Wembley on Sunday for their first clash in the UK this season.
Meanwhile, Arsenal will resume their training this week ahead of their Premier League match against Queens Park Rangers on Saturday.