[python] How to form tuple column from two columns in Pandas

I'd like to add df.values.tolist(). (as long as you don't mind to get a column of lists rather than tuples)

import pandas as pd
import numpy as np

size = int(1e+07)
df = pd.DataFrame({'a': np.random.rand(size), 'b': np.random.rand(size)}) 

%timeit df.values.tolist()
1.47 s ± 38.9 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)

%timeit list(zip(df.a,df.b))
1.92 s ± 131 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)