A face grooving tool body, comprising a blade portion comprising a top surface, an opposite bottom surface, a first side surface and an opposite second side surface, a front end and an opposite rear end, a longitudinal axis of the blade portion coinciding with a primary cutting feed direction of the blade portion, an upper blade portion associated with the top surface and a lower blade portion associated with the bottom surface, wherein the upper and lower blade portions (61, 62) are separated by a slit extending from the front end to a rear slit end, the slit intersecting the first and second side surfaces (55, 56), the slit comprising an insert seat for a grooving insert, the insert seat opens in the front end, the insert seat comprises an upper clamping surface formed in the upper blade portion, an opposite lower support surface formed in the lower blade portion, and a rear support surface formed in the lower blade portion, wherein the lower support surface extends a greater distance from the rear end than a distance the upper clamping surface extends from the rear end, wherein the second side surface of the lower blade portion is curved around a second side surface axis of curvature extending parallel to the longitudinal axis, wherein the slit comprises a slit portion, wherein the slit portion extends between a slit portion front end and a slit portion rear end, wherein the slit portion is located between the rear slit end and the insert seat, wherein a distance from the bottom surface to rear slit end is greater than a distance from the bottom surface to the slit portion front end where the distances (71, 72) are measured in planes perpendicular to the longitudinal axis, characterised in that a key hole is formed in the blade portion, wherein the slit portion, or a major portion of the slit portion equal to at least 50% of the length of the slit portion, is concave in a side view such that the upper blade portion adjacent to the slit portion, or adjacent to the major portion of the slit portion, is concave and such that the lower blade portion adjacent to the slit portion, or adjacent to the major portion of the slit portion, is convex. a blade portion comprising a top surface, an opposite bottom surface, a first side surface and an opposite second side surface, a front end and an opposite rear end, a longitudinal axis of the blade portion coinciding with a primary cutting feed direction of the blade portion, an upper blade portion associated with the top surface and a lower blade portion associated with the bottom surface, wherein the upper and lower blade portions (61, 62) are separated by a slit extending from the front end to a rear slit end, the slit intersecting the first and second side surfaces (55, 56), the slit comprising an insert seat for a grooving insert, the insert seat opens in the front end, the insert seat comprises an upper clamping surface formed in the upper blade portion, an opposite lower support surface formed in the lower blade portion, and a rear support surface formed in the lower blade portion, wherein the lower support surface extends a greater distance from the rear end than a distance the upper clamping surface extends from the rear end, wherein the second side surface of the lower blade portion is curved around a second side surface axis of curvature extending parallel to the longitudinal axis, wherein the slit comprises a slit portion, wherein the slit portion extends between a slit portion front end and a slit portion rear end, wherein the slit portion is located between the rear slit end and the insert seat, wherein a distance from the bottom surface to rear slit end is greater than a distance from the bottom surface to the slit portion front end where the distances (71, 72) are measured in planes perpendicular to the longitudinal axis, characterised in that a key hole is formed in the blade portion, wherein the slit portion, or a major portion of the slit portion equal to at least 50% of the length of the slit portion, is concave in a side view such that the upper blade portion adjacent to the slit portion, or adjacent to the major portion of the slit portion, is concave and such that the lower blade portion adjacent to the slit portion, or adjacent to the major portion of the slit portion, is convex.