The appointments are the first creative signings by the new CHI executive creative director, Ewan Paterson, who joined the agency from Bartle Bogle Hegarty this month.
Wardlaw, 38, and Berwitz, 32, met at St Martin's School of Art, where they studied Product Design. They will work across a number of accounts at the agency, and will lead the creative duties on CHI's Toyota business.
Before their six-month spell at MCBD, they spent seven years at Euro RSCG London, where they created the Peugeot 1007 "easy life" spot.
The ad is a mixture of live action and animation and was directed by Antoine Bardou-Jacquet.
While at the agency, they also created the "envy" and "shame" spots for the Peugeot 307, which were directed by Fredrik Bond and Nicolai Fugslig, respectively.
Paterson said: "I've been a big fan of their work for some time now. I talked to them as soon as I took on the role at CHI and it is great to be able to entice them to the agency.
"They are a team on their way up and, from the work they do and the kind of people they are, will be perfect for this place."
Paterson joined CHI to take over the day-to-day running of the agency's creative department from the CHI co-founder Charles Inge. Inge's role has been expanded to oversee the creative output of the entire CHI group.
Before joining BBH, where he oversaw the Boddingtons, Castlemaine XXXX and Flora accounts, Paterson spent nine years at DDB London.