The 35-year-old has signed up for Middlesex's first seven group matches, starting in July, but is also available for the tournament's latter stages.

De Villiers retired from international cricket in 2018, having scored more than 20,000 runs in all three formats.

"I have always wanted to play county cricket," De Villiers said.

"Playing at Lord's is always a wonderful privilege, and I'm looking forward to the match at Richmond, a beautiful ground in south-west London. That will be a great experience."

De Villiers is one of the world's best-known Twenty20 players and has scored 7,316 runs in 272 games at a strike-rate of 148.85.

He has taken part in every Indian Premier League since it started in 2008, as well as numerous other T20 competitions across the world.