Smith, second in the Test batting rankings, will be available for County Championship matches against Worcestershire, Leicestershire and Glamorgan before the first Ashes Test starts at Edgbaston on June 16.

The signing of the former Australia captain, who averages more than 60 in 92 Tests, will give him valuable batting practice in English conditions.

"I am excited about joining Sussex for a few games in May and hopefully making a contribution to a successful season," said Smith, who is currently playing in the Big Bash League for the Sydney Sixers.

"I am particularly looking forward to working with the younger players in the squad and hoping I can provide some guidance to them."

Sussex Cricket CEO Rob Andrew said he was delighted by the high-profile signing.

"To have arguably the world's best batter play for Sussex just before an eagerly awaited Ashes Test series is great for us and the County Championship," he said.

"Being able to attract a player of Steve Smith's calibre is a massive statement and will be of great benefit to our young homegrown players, particularly our crop of talented young batters."

Smith joins India Test batter Cheteshwar Pujara (34), who previously agreed a return to Sussex for the 2023 season.

Australia will be defending the Ashes in a five-Test series in June and July. The last time the two sides met, Australia won 4-0 at home with the last series in England - back in 2019 - was a 2-2 draw.