James Allison, Mercedes' new technical director, reported to duty for the first time yesterday in Barcelona, wearing his new team colors.
Allison left Ferrari last summer, in need of some personal down time following the tragic loss of his wife earlier in the year.
But his expertise was quickly picked up by Mercedes which sought a replacement for its own departing tech boss Paddy Lowe.
"His skills and personality perfectly complement the team," team boss Toto Wolff told Italy's Corriere della Sera.
"We share the same spirit. For a long time we thought he was the right man for our type of organisation, but he was not available.
"He comes from a terrible period with his family tragedy and last year in which Ferrari did not meet the expectations of president Sergio Marchionne.
"But he is very motivated and we will help him turn the page," Wolff added.
Allison's former team, Ferrari, has enjoyed a good performance level since pre-season testing got underway last week, and Wolff has taken notice.
"Yes," he said, "although I still don't know who will be our strongest rival. But Ferrari is proving to be very fast.
"Red Bull is still difficult to judge but they will be there."