West Ham host Andorran side Lusitanos at Upton Park tonight as they aim to get through the qualifying rounds and reach the Europa League group stages.
Defender Tomkins will captain the club on the night and 26-year-old midfielder Collison has sent a special Twitter message to the man, as well as his former club as a whole.
Collison was at West Ham until he was released in 2014 and is now at Peterborough United.
The excitement has been building for the Hammers all summer and the Boleyn Ground will no doubt be rocking as West Ham re-enter European competition tonight.
It'll be a big day for Tomkins, too, and all those at West Ham will no doubt appreciate the support from their former player in Collison.
Kick-off at Upton Park will be at 7.45pm, with the reverse fixture in exactly a week's time next Thursday night.