Kenzo Graphic Trees Shirt
Q (Ben Whishaw) wears a Kenzo Graphic Trees shirt in cobalt blue in the 2015 movie SPECTRE.
Q wears the Kenzo shirt in the scene at Q's lab, when Bond gets his Omega Seamaster 300 SPECTRE limited edition and they look at the 009's Aston Martin DB10.
It can also be seen in the Red Nose Day Comic Relief charity campaign in which Ben Whishaw and Daniel Craig participated.
This designer Kenzo shirt is 100% cotton, product number F465CH0001KM. The shirt is currently difficult to find, but one seller on eBay has a few sizes of the shirt (cirillomoda is a trusted seller, I purchased a shirt from this seller and it was shipped via DHL the next day).
Kenzo uses the same graphic trees design for a windbreaker jacket, and a neck tie, both of which are now also sold out everywhere.
Kenzo is a French luxury house founded in 1970 by Japanese designer Kenzo Takada. The brand is now owned by LVMH (Louis Vuitton Moet Hennessey), that purchased the label in 1993.
Q seems to prefer red and blue graphic designs in SPECTRE: he also wears a red and blue design sweater by Paul & Joe.
With the shirt, Q wears his Univo U5 eyeglasses. The rest of the outfit is not yet indentified.