"Craig has gained excellent experience having been a professional for two years," he said. "What he has lacked is consistent game time, mainly due to a number of injuries.
"There is no doubt that he will strengthen our squad and will be one of three quality tight heads challenging for the shirt."
Cross has returned to the Drovers following a two year spell at the Ospreys where he made just five appearances. He also turned out regularly for Swansea and Aberavon.
Weighing in at nearly 22 stone and at 6ft 5 inches tall, Cross will provide a physical presence in the Llandovery pack.
But the former Osprey is far from guaranteed a starting spot and will have to compete with veteran Andrew Jones and Dean Howells who starred in the front row last season.
Cross's first opportunity to wear the Llandovery shirt will be this Saturday as the Drovers take on Pontypridd in their latest pre-season fixture.
Llandovery welcome Pontypridd after combining a good performance with a 38-29 win against Cinderford last weekend. All members of the squad are expected to be given a run out against Ponty.
Last year's Premiership champions will provide stern opposition but Lewis believes it is another key step with their first league game just two weeks away.
"It is important that we measure ourselves against the best and that we challenge our players to outperform the best," he said.
"We value Pontypridd and everything they stand for. It is a high quality pre-season match which we hope everybody will enjoy watching.
"Ponty are the best side in the Premiership with a great set of supporters and Saturday's game will provide all of our squad with an opportunity to book a place in the squad for next week's key game against Bath."