Kohli and Williamson, two of the best batsmen across all formats, now feature in the top-5 standings of Test, ODI and T20Is. At present, they are the only 2 to achieve this.
When the ICC rankings were updated on Monday, Williamson moved up two places to be at 4th position in T20Is.
The Kiwi right-hander had a good series against Bangladesh, scoring 145 runs (73 not out, 12 and 60). New Zealand whitewashed Bangladesh 3-0. Williamson is at 4th place in Test rankings and 5th in the ODI table.
The 28-year-old Kohli, who was recently appointed as India's ODI and T20I captain, is ranked 2nd in both Tests and ODIs. He is the number one in T20Is.
"India's Virat Kohli is the only other batsman (apart from Williamson) in the world who presently features in the top five of all three formats. He is the number-one ranked batsman in T20Is, second-ranked in ODIs and ranked number-two in Tests," ICC said in a media release.
"Interestingly, both Kohli and Williamson captained their respective sides in the ICC U19 Cricket World Cup 2008 in Malaysia. India won the tournament when it defeated South Africa by 12 runs (Duckworth/Lewis method)," it added.
ICC Rankings for Players - Top 5 (As on January 9, 2017)
1. Steve Smith (Australia) - 933 rating points
2. Virat Kohli (India) - 875
3. Joe Root (England) - 848
4. Kane Williamson (New Zealand) - 817
5. David Warner (Australia) - 812
1. AB de Villiers (South Africa) - 861
2. Kohli - 848
3. Warner - 846
4. Quinton de Kock (South Africa) - 779
5. Williamson - 770
1. Kohli - 820
2. Aaron Finch (Australia) - 771
3. Glenn Maxwell (Australia) - 763
4. Williamson - 758
5. Faf du Plessis (South Africa) - 741