The different between SKlearn and statsmodels in calculting R2

Question

I calculate the R Squreed using Statsmodels and SKlearn package, but the results are different. I can't figure out what could be the reason

import statsmodels.api as sm
X_addC = sm.add_constant(X)
result = sm.OLS(Y, X_addC).fit()
print(result.rsquared, result.rsquared_adj)
# 0.79180307318 0.790545085707

print(r2_score(Y,X))
# 0.65