Katie Price's ex-boyfriend is said to have met the model at the book launch for The Only Way Is Essex star Chloe Sims last week, according to The Mirror.
McLean - who is reportedly fluent in Penna's first language Spanish - was later spotted with him at the Attic Bar in Canary Wharf, London, before leaving for Tiger Tiger.
A source said: "Sarah studied Spanish at uni, so they could speak to each other throughout the meal.
"They were touching hands and giggling."
Their first date allegedly ended with Penna inviting McLean back to his London flat on Saturday (November 17).
> Katie Price: 'Leandro Penna gave me cystitis all the time'
The source added: "They are getting on but are trying to keep it very low-key."
Leandro Penna and Katie Price ended their relationship last month, after first meeting in early 2011. They announced their engagement in April 2012.
The Argentinian recently stated that the final straw in their relationship was Price messaging District3 member Dan Ferrari-Lane.
Sara McLean took part in the 13th series of Big Brother on Channel 5 earlier this year. She finished in fourth place.