Khan, who met Tourism Minister Ambika Soni personally to receive the offer officially in the national capital Friday, said he was more than happy to be part of the campaign.
"I have accepted the invitation. I am very happy to be part of it. It is a wonderful country and 'incredible' is the fitting word for it, " Khan, who was wearing a black T-shirt over rugged and torn jeans, told reporters at Soni's residence here.
However, the ministry is yet to finalise the type of campaign it wants to do for the coming year.
"We will be coming out with an ad campaign and a road show to promote India's tourism. It will highlight the culture and heritage of the country, which are the USPs of our country, " the minister said.
The actor, who said he would be working free of cost for the campaign, appeared to have a fair idea about what he was going to do.
"We should show our hospitality. India is famous for it. Even if there are some incidents, we should take steps to sensitise people, " he said.
"Each social work is different. Through this, I want to remind people how great is our country and want to sensitize our people. I want to tell them what we are -- we are warm and hospitable people. We have to protect those who are visiting our country. We must ensure that they have a good time and come back again."
The 'Incredible India' campaign launched in 2002, showcasing the country's unique heritage and cultural aspects, has been a major hit and made considerable impact on its tourism sector.
Khan made it clear that his participation was a part of his social commitments and he had no plans to enter politics.
"I am an entertainer and will continue to do good work. I am part of it because I want to spread social message."
Earlier, Shah Rukh Khan was a part of the campaign for creating awareness on garbage disposal.
According to Aamir, films are good way to showcase India. "After the movie 'Lagan', wherever I go, I used to meet people who were interested in visiting India."
Asked if the recent terror attacks - in Bangalore and Ahmedabad - would damage the country's aspirations in the tourism sector, Aamir said: "Terrorism is against everyone. We should be united. We are for peace and if there is one bomb blast, we should light a billion candles."
"If they (terrorists) are spreading poison, we should spread the message of love and peace, " he said.
Bollywood director Rakeysh Omprakash Mehra and lyricist Prasoon Joshi were also present.