A new technique is developed to identify dielectrons (
e
+
e
−
) with Lorentz boost
γ
L
>
20
that produce one single merged cluster in the electromagnetic calorimeter of the CMS detector. The identification uses two multivariate models: one for the case where both electron tracks are reconstructed, and another where only one of the tracks is reconstructed. The efficiency is determined using proton-proton collision data collected at a center-of-mass energy of 13 TeV. Boosted
J
/
ψ
mesons decaying into
e
+
e
−
pairs are used to estimate the efficiency of the model with two tracks, yielding an overall efficiency of 80%. The
Z
→
μ
+
μ
−
γ
events, where the photon converts into a collimated dielectron, are used for the model with a single track, yielding an efficiency of about 60%. A dedicated energy correction for dielectron candidates is also developed using
B
±
→
J
/
ψ
K
±
→
e
+
e
−
K
±
data.
