Middlesex have signed Dirk Nannes, the Australian left-arm fast bowler, and Vernon Philander, the South Africa allrounder, for 2008.
The pair replace Friedel de Wet and Ashley Noffke, neither of whom will be available to the county. Noffke was included in Australia's squad for the Caribbean tour starting next month.
Philander, 22, joins as an overseas player and will stay at Lord's until the arrival of Murali Kartik in June. Nannes, meanwhile, holds a Dutch passport and is not classed as an overseas player.