The Gunners announced the signing of the 17-year-old this afternoon.
Arsene Wenger's... interesting... approach to the January transfer market continued this afternoon, with Arsenal confirming the signing of Krystian Bielik.
The 17-year-old Polish midfielder joins the Gunners with the unique selling point that he can play both in defensive midfield and at centre-back - two notorious problem positions at the Emirates Stadium.
And yet, with the race for a place in the Premier League's top four so wide open, Arsenal's first signing is an unproven teenager who is, once again, to be categorised as 'one for the future.'
The reaction on Twitter has, predictably, been mixed. Most Arsenal fans do seem pleased that Bielik is joining up with the Gunners and have been keen to welcome him to north London.
Some haven't been able to resist pointing out, however, that Bielik was unknown to many before interest in the new Arsenal signing became public - and that he is far from the proven signing many feel Wenger needs.
It will certainly be intriguing to see how the 17-year-old fits into English football and whether Wenger uses him as soon as possible or keeps him on the fringes while he settles into life in the Premier League. Here is a selection of the best Twitter reaction from Arsenal fans...
I like how the tagline for the Bielik story on the Arsenal website is "Can play holding midfield and centre back" #AFC— Liam (@FootieLiam) January 21, 2015
Bielik will likely be given all the time in the world to adapt to the Premier League's pace and physicality. But a good signing. #afc— Byron la Hoe (@ByronLaHoe) January 21, 2015
AFC_Harry34) January 21, 2015
Like Bielik is hardly a signing to me. Anyone that thinks he'll get in your squad, recover yourself.— Jack (@CoveringKosc) January 21, 2015
Arsenal's twitter account don't seem very excited about Bielik, usually they don't stop going on..— Arsenal (@ffarsenalfc) January 21, 2015