This is how Aaron Donald celebrated his quarantine birthday this year ... by coppin' a flossy diamond pendant featuring his jersey number!!
TMZ Sports has learned .. the L.A. Rams defensive beast hit up Mohsen Syed (aka Moe Diamonds) in Pittsburgh last month to get a dope chain ready for his 29th birthday on May 23.
Moe tells us he personally went over 7 to 10 designs with Donald before they came up with the perfect look ... just in time for AD to get it on his birthday.