Speaking to the Daily Star, the source revealed that NBC Universal, who make the drama, are willing to offer a multi-million dollar donation to a charity of Meghan's choice if she decides to come back for one more episode.
The role would show Meghan's character Rachel Zane as pregnant in a two minute clip that is planned to be shot in the UK.
"We could be done in half a day or less," said the source.
Although no final figure has been arrived at, it is believed that negotiations are "likely to be opened in the very near future," and that "sums ranging from two to six million" are being tossed around.
If the figure is as substantial as speculated, "it would be one of the biggest marketing coups in TV history," revealed the source.
Meghan starred on Suits from 2010 but left the show in order to concentrate on her charity projects and to marry Prince Harry in May 2018.
Her final episode with the show was aired just a month before her royal wedding.
The final episode Meghan filmed showed her character get a happy ending by marrying her on-screen boyfriend Mike Ross, portrayed by Patrick J Adams.
NBC bosses have revealed that Rachel's storyline would mirror that of Meghan's which would show her pregnant and living in the UK.
When Meghan wed Harry, most of her co-stars were invited to the wedding. Among the attendants were Patrick J Adams, as well as Gabriel Macht, who portrays Harvey.