WATCH: Per Mertesacker got the giggles at the worst possible moment today

The Arsenal defender needs to work on his stone face.

Per Mertesacker seems like the kind of guy who would find a reason to laugh in most situations.

And it is generally a good thing to be a light-hearted, glass-half-full type of person.

But the Arsenal defender should consider working on his stone face for those situations when it is definitely not appropriate to burst out laughing.

Such as when discussing your manager’s future at a packed press conference being screened on TV.

Mertesacker got a fit of the giggles when a reporter asked about Arsene Wenger’s future with the club, before realising how ill-timed it was.

He quickly reverted to a serious expression but his outburst had not gone unnoticed.

LOOOOOOOOOOOOOL Mertesacker's reaction 😂😂 pic.twitter.com/R9T4kfDYMD

— SJ (@sarahjayneeee_) March 6, 2017

Awkward dynamic between Wenger and Mertesacker when questions raised on players fighting and wanting AW in charge.. #AFC

— Mark Mann-Bryans (@MMBonF1) March 6, 2017

Can't stop laughing at how wrong Mertesacker gets this... https://t.co/MZF0eJdlaN

— Si Lloyd (@SmnLlyd5) March 6, 2017