A deal would create a toy powerhouse, uniting Hasbro's My Little Pony, Monopoly and Nerf brands with Mattel's Barbie dolls and Hot Wheels toys.
The stance by Mattel toward Hasbro related to this approach is not known and it remains far from being certain a deal will eventually materialize, said the source, who asked to remain anonymous since the matter was confidential. The two companies declined to comment to the outlet, and the likelihood of the deal's success is unclear.
Mattel's shares jumped 20 per cent in after hours trading, while Hasbro rose 2.2 per cent.
Talks that the two may join forces has been long rumored, as Mattel's stock has fallen a significant 52 percent over the past year, leaving its market value at $5 billion.
The September bankruptcy of Toys "R" Us, the biggest USA toy retailer, highlighted the struggles facing the sector, including online competition and children's shifting preference for electronics over traditional toys. Last month the company suspended its dividend and warned it would miss forecasts for revenue this year.
But, the deal could be an opportunity for Mattel, which has struggled financially in recent years.
Hasbro is attempting to diversify revenue streams, and has sought to acquire movie studio and entertainment business Lions Gate Entertainment, but the talks were ended without any deal coming to fruition. And it maintains a strong relationship with Hollywood - Hasbro also makes toys for successful Disney franchises.